A retrieval study on morphological and chemical changes of titanium osteosynthesis plates and adjacent tissues.

AIM: To examine (a) morphological and chemical changes of retrieved titanium osteosynthesis plates, (b) findings in adjacent soft tissues during plate removal and to evaluate possible correlations among the above-mentioned issues. MATERIAL AND METHODS: Ninety-four osteosynthesis plates were retrieved, of which 60 were studied and evaluated (including the adjacent soft tissue) in more details, 4-36 months following osteosynthesis in 26 trauma cases, 12 orthognathic and 6 maxillofacial reconstructive cases. Selected clinical parameters during plate removal, were studied. Specialized laboratory methods including light and electron microscopy as well as spectrometry and X-ray microanalysis were used to analyse the retrieved material. RESULTS: Plates showed major mechanical changes (scratches, scraping and deformation) without corrosion. Soft tissue inflammation-mainly mild and chronic-was found in 53 of 94 plates removed, a statistically significant percentage. Pigmented deposits in the soft tissues manifested only traces of titanium when analysed elementally. There was no statistically significant correlation between the laboratory findings of plates and tissues, or between plate morphology and clinical findings recorded. CONCLUSIONS: According to the findings of this study, inflammation in tissues adjacent to osteosynthesis plates should not be attributed to mechanical changes in the plates. Pigmented tissue deposits were neither found to be titanium to the extent previously reported, nor were they correlated with tissue inflammation. These findings lead to the assumption that titanium plates do not have to be removed to avoid local inflammatory problems.     

The use of titanium mandibular reconstruction plates in patients with oral cancer.

A series of 21 patients, who were selected for primary mandibular stabilisation with titanium plates following excision of advanced malignant tumours, is reported. Success was defined as a plate that did not have to be removed due to fracture, exposure or infection. The overall success rate was 71%, with follow-up ranging from 7-53 months. The majority of plate losses were experienced when either anterior or large lateral defects which included the condyle were bridged and when patients were subjected to either pre- or postoperative radiotherapy.     

Tissue regeneration adjacent to titanium implants placed with simultaneous transposition of the inferior dental nerve: a study in dogs

Transposition of the inferior alveolar nerve was performed in an experimental dog model. Four adult greyhounds were used in the study. Surgical transposition of the nerve was made bilaterally, and 3 implants were placed on each side while the nerve was lateralized. On one side, the nerve was repositioned in contact with the implants, while on the contralateral side a resorbable membrane was positioned between the implant surface and the neurovascular bundle. Histologic section after 4 months of healing showed an intimate contact between implants and nerve tissue in all cases without an interpositional membrane, in contrast to cases with membranes. Histomorphometric measurements of the distance between the implants and the nerve tissue showed that the membrane side had a considerably larger distance between the implant and the nerve, although not with concomitant bone formation.     

BMP stimulation of bone response adjacent to titanium implants in vivo

The objective of this study was to evaluate the effect of bone morphogenetic protein (BMP) on the bond strength of titanium (Ti) implants at the bon-implant interface. Thirty-six Brånemark screw implants (3.75 mm diameter by 15 mm long) were implanted for 3 and 12 weeks. At 3 weeks after implantation, the mean reverse torque value for implants stimulated with BMP delivered using an atelopeptide type-1 collagen carrier (74.2±5.2 N cm) was observed to be statistically greater (P<0.000016) than the mean reverse torque value for control Ti implants (32.8±1.1 N cm). Similarly, at 12 weeks after implantation, the mean reverse torque value for implants stimulated with BMP (89.2±2.7 N cm) was statistically greater (P<0.0042) than the mean reverse torque value for control Ti implants (75.8±2.4 N cm). In addition, hisiomorphometric evaluations indicated more bone contact with the BMP stimulated implant surfaces compared to the controls after 3 weeks implantation. It was concluded from this study that the use of BMP-atelopeptide type-1 collagen mixture is an effective means of obtaining greater bond strength at the bone-implant interface within a shorter time period than Ti implants without BMP.     

Surface analysis of titanium maxillofacial plates and screws retrieved from patients

This investigation is a controlled human plate-retrieval study. The surface appearances and elemental composition of 50 titanium maxillofacial plates and associated screws retrieved from 39 patients were compared with a control sample of unused plates and screws using stereomicroscopy, scanning electron microscopy and energy dispersive X-ray analysis. There were two surface finishes, either anodized or non-anodized. Surface contamination was detected on both retrieved and control plates consisting of aluminium and silica and was more commonly present on non-anodized specimens. Manufacturing defects comprising rough metal edges and protuberances were identified on the unused controls and surgical damage was evident on the retrieved specimens. There were no signs of corrosion or surface deterioration on the retrieved plates and screws which had been in the tissues for between 1 month and 13 years. There was no evidence from this study to support the routine removal of titanium maxillofacial miniplates plates due to corrosion up to a period of 13 years.     

Tissue response to implanted ceramic-coated titanium alloys in rats

In order to assess the tissue compatibility of the hybrid materials for the dental implant (hydroxyapatite, titanium oxide and titanium nitride coated titanium alloys), tissue response to these materials implanted in the rat subcutaneous tissue was histologically examined. Initial inflammatory response was less evident in titanium oxide coated and non-coated titanium alloys. All materials were encapsulated by thin fibrous connective tissues. The membrane thickness of hydroxyapatite coated titanium alloy was significantly higher than that of titanium nitride coated one. These results suggest that all materials possess favourable tissue compatibility and may encourage clinical use as the dental implant.     

Validation of computer-assisted manufacture of titanium plates for cranioplasty.

We have constructed 300 titanium cranioplasty plates, over 150 cases using a computerised technique, the remainder by external impression. The clinical follow-up of these cases over 8 years has shown consistently good results that justify our simple low-cost method of manufacturing these plates. Both techniques require the provision of a model on which to construct the plate. In the traditional technique, an approximate model is derived from the resected bone or a direct impression of the defect over the patient's scalp. Using the computerised technique, a more accurate model of the defect and the surrounding bone is milled in polyurethane foam from cross-sectional computerised tomographic (CT) scans. Sheet titanium is pressed to shape from a design outlined on a counterdie. The subsequent stages of the plate construction are then the same for both methods. This study describes the stages of the model manufacture, the validation of its accuracy and the plate construction that follows. Use of the computerised method has resulted in a reduction of errors, enabling the manufacture of a smaller plate than was possible previously. It has also enabled design changes through the achievement of greater accuracy in fit.     

Bond strength of resin cements to H2O2-treated titanium plates.

OBJECTIVE: This study investigated the effects of H(2)O(2)-treatment of titanium surfaces on cement shear bond strengths, and characterized H(2)O(2)-treated titanium surfaces. METHODS: Using 34.5% hydrogen peroxide solution, cp Ti plates (10 mm x 10 mm x 1 mm) were treated by (1) an immersion method, and (2) halogen irradiation while immersed in H(2)O(2) for varying times. A cylindrical block (6 mm diameter, 4 mm height) of four different cements was bonded onto H(2)O(2)-treated surfaces. The cement bond strengths were evaluated under shear mode. Treated surfaces were also characterized for color change, wettability, AC impedance, and transmission electron diffraction of stripped oxide film. RESULTS: The cement shear bond strength of cp Ti treated with H(2)O(2) and halogen for 160 s was the highest and was approximately 14 times higher than the un-treated control cp Ti plates. Bond strengths are correlated linearly to wettability. The more surface wetted with the cement material, the higher the resultant shear bond strength value. SIGNIFICANCE: These results suggest that a combined treatment of hydrogen peroxide and halogen light irradiation provides an effective surface condition with appropriate oxide film thickness to enhance the cement bond strength.     

Distortion of laser welded titanium plates

The distortion of laser welded titanium plates was assessed for different operating conditions of the laser welding device, and with different welding parameters (in terms of weld point and prewelding). In this study, Nd : YAG laser welding device was used to join the titanium plates. The results showed that distortion increased stepwise after each welding point along the welding zone (one-side welding), but decreased consecutively as the welding proceeded on the second side of the weld (two-side welding). In the case of one-side welding, the dependence of distortion on current and spot diameter presented maxima--due to changes in the welding pool characteristics. For two-side weld the same parameters exercised little influence on its distortion recovery, due to the effect of solidified weld pools from the first side. Current and spot diameter determined the weld pool, which in turn regulated distortion based on shrinkage. Four-point prewelding significantly decreased the final distortion for both one- and two-side welds. Alternating two-side welding of prewelded assembly showed lower distortion than a classic two-side weld.     

Immunocompetent cells adjacent to stainless steel and titanium miniplates and screws

Subepithelial soft tissue and bone obtained from the implant bed in the vicinity of stainless steel and titanium miniplates and screws were evaluated with respect to the presence of immunocompetent cells. The study included tissue specimens from 19 patients, in whom the implants (14 stainless steel and 5 titanium) had been in situ for more than 6 months. The ABC (avidin-biotin-complex) immunoperoxidase staining technique using monoclonal antibodies defining T lymphocytes (CD3⁺), macrophages (CDllc⁺) and Class II MHC (HLA-DR) was performed on EDTA demineralized, frozen bone tissue, and on fresh frozen soft tissue specimens. The results showed scattered T lymphocyte clusters, small numbers of macrophages and abundant expression of HLA-DR in the soft tissue adjacent to both stainless steel and titanium implants. There was no substantial difference in tissue reactions between implants of the two materials. The demineralized bone sections disclosed presence of immunocompetent cells in the connective tissue lining the periphery of the screw holes. Metal particles were seen in both the soft tissue and the bone specimens. We conclude that a mild tissue reaction takes place in the vicinity of miniplates and screws of stainless steel and titanium, and that the intensity of the reaction indicates that the implants are well tolerated by the host tissue.     

Radiographic evaluation of crestal bone levels adjacent to nonsubmerged titanium implants

Several parameters have been described to determine success or failure in long-term evaluations of dental implants. One of these parameters is the observation of changes in peri-implant bone levels. Studies on submerged implants have analyzed the bone level changes in the pre- and post-loading phases. No such data exist for intentionally nonsubmerged implants. The purposes of this study were: (1) to test the applicability and reproducibility of a simple computer-assisted method in the evaluation of changes in peri-implant bone levels; (2) to establish a baseline for the longterm radiographic follow-up; and (3) to evaluate changes in crestal bone levels adjacent to nonsubmerged ITI implants between the 1-year and 2-year examination. Standardized periapical radiographs were obtained from 80 implants at the 1-year and 2-year follow-up examinations after their placement. The implants were located in different jaw areas of 55 patients and supported single crowns or short-span fixed partial dentures. For each implant, the distance from implant shoulder to first crestal bone contact (DIB) was measured at the proximal surfaces with a digitizer/computer assembly. Statistically significant greater mean DIB were found at the 1-year (baseline) evaluation for: (1) maxillary sites overall (4.10 x 1.02 mm (SD)) compared with mandibular sites overall (3.61 +/- 1.03 mm); (2) maxillary anterior sites (4.08 +/- 0.97 mm) compared with mandibular posterior sites (3.60 +/- 1.05 mm); and (3) maxillary posterior sites (4.13 +/- 1.12 mm) compared with mandibular posterior sites. No statistically significant changes in DIB occurred in any of the jaw locations between the 1-year and 2-year evaluations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bone reactions adjacent to titanium implants subjected to static load. A study in the dog (I)

The aim of the study was to evaluate the effect of lateral static load induced by an expansion force on the bone/implant interface and adjacent peri-implant bone. In 3 beagle dogs, the 2nd, 3rd and 4th mandibular premolars were extracted bilaterally. Twelve weeks later 8 implants of the ITI Dental Implant System were placed in each dog. Crowns connected in pairs were screwed on the implants 12 weeks after implant installation. The connected crowns contained an orthodontic expansion screw yielding 4 loading units in each dog. Clinical registrations, standardized radiographs and fluorochrome labeling were carried out during the 24-week loading period. Biopsies were harvested and processed for ground sectioning. The sections were subjected to histological examination. No evident marginal bone loss was observed at either test or control sites. The bone density and the mineralized bone-to-implant contact were higher adjacent to the lateral loaded implants than at the unactivated control sites. It is suggested that the static load applied to implants in a lateral direction resulted in a structural adaptation of the peri-implant bone.     

Histologic study of the bone adjacent to titanium bone screws used for mandibular fracture treatment.

PURPOSE: Titanium miniplates have been widely used in mandibular fracture fixation because of their strength and excellent biocompatibility. However, the condition of the bone adjacent to titanium bone screws has not been clarified. This study histologically examined the bone-screw interface in patients treated for mandibular fractures. PATIENTS AND MATERIALS: Specimens were obtained from 14 patients, and the undecalcified sections were stained by the toluidine blue and Levai Laczko methods and examined with light microscopy. The mean ratio of direct contact between the bone and the titanium bone screw surface was also analyzed using a computer-aided image analyzer. RESULTS: The formation of new bone was observed around the titanium bone screws in all cases. In areas of cortical bone, partial interposition of soft tissues was rarely observed. However, in areas of cancellous bone, partial interposition of soft tissues was seen, and bone resorption between the bone and soft tissues was noted. The mean ratio of direct contact between all of the adjacent bone and the surface of the titanium bone screws was 64.4%. The mean ratio of direct contact between cortical bone and the titanium bone screws was 82.4%. Black particles were observed in the bone and soft tissues around the titanium bone screws, and multinuclear giant cells resembling macrophages were observed near these particles. CONCLUSION: Titanium bone screws used for mandibular fracture fixation develop almost complete contact with new bone. Some metalosis is present.     

Tissue changes in immature dog teeth autotransplanted to surgically prepared sockets.

Tissue reactions in teeth autotransplanted to surgically prepared sockets were investigated by means of microangiographic, enzyme histochemical, and histologic methods. The experimental material consisted of 28 immature teeth in six mongrel dogs. In each tooth, approximately three fourths of the root was formed at the time of transplantation. Ten days after transplantation, a vascularized, well-stained connective tissue was observed in the apical area of the pulp. An ingrowing tissue had reached the pulp horn in all teeth 90 days after surgery. Odontoblasts were not found in any of the transplanted teeth. External root resorption was seen in all teeth but repair usually occurred approximately parallel to the ingrowth of new tissue into the pulp cavity. In a few teeth, however, advanced inflammatory root resorption was observed in cracks in the cervical area. When compared with the results of a previous study, the ingrowth of tissue occurred at a considerably slower rate than in teeth autotransplanted to natural sockets.     

Anode glow discharge plasma treatment of titanium plates facilitates adsorption of extracellular matrix proteins to the plates

Glow discharge plasma (GDP) supplied to an anode (GDP+) promotes calcium phosphate adsorption onto titanium better than that supplied to a cathode (GDP-). However, the adsorption of extracellular matrix (ECM) proteins is crucial for cell adhesion to titanium. Since GDP+ induced both inorganic adsorption and cell adhesion, we hypothesized that the inorganic adsorption in a culture medium might affect the adsorption of the ECM proteins. In this study, ECM proteins adsorbed on titanium with and without GDP were examined by x-ray photoelectron spectroscopy. After 1 hr of incubation, increasing sodium adsorption on GDP+ specimens induced adsorption of ECM proteins as shown by NH(+) and COO(-) signals without calcium adsorption. In contrast, since no specific adsorption of sodium on GDP-specimens was detected, GDP-did not contribute to the adsorption of ECM proteins. Thus, promotion of sodium adsorption of GDP+ was effective, at least in the initial ECM protein adsorption on a titanium surface.     

Follow-up examinations after removal of titanium plates coated with anodic titanium oxide ceramic

Transformation of the titanium metal surface with titanium oxides produced in various ways belongs among the most up-to-date procedures. The authors as pioneers in this field (e.g. Nobel Biocare TiUnite surface), have been utilizing for more than 15 years dental root implants and fixing elements (for mandibular osteosynthesis) coated with titanium oxide ceramics, produced by anodic oxidation and thermal treatment. The aim of this work was to assess the extent to which a titanium oxide ceramic coating influences the fate of plates applied for osteosynthesis within the human body. During a 5-year period (1995-1999), 108 of 1396 titanium oxide ceramic plates had to be removed for various reasons: loosening of the plate [47], osteomyelitis [25], a palpable swelling and tenderness [21] at the request of the patient for psychological reasons (13) or breaking of the plate [2]. When these 108 plates were removed, it was not possible to detect metallosis in even a single case; nor was there any tissue damage that could be attributed to the surface of the plates, whereas the literature data indicate that such damage is relatively frequent in the environment of traditional titanium fixing elements. The present investigation confirms the favourable properties of the titanium oxide ceramic surface.     

Removal of titanium plates coated with anodic titanium oxide ceramic: retrospective study

Transformation of the surface of metallic titanium with titanium oxides prepared in various ways is a modern procedure. For more than 15 years, the authors have been utilizing fixing elements coated with titanium oxide ceramics, prepared by anodic oxidation and thermal treatment, for purposes of jawbone osteosynthesis. The aim of the authors' work was to assess the extent to which the titanium oxide ceramic coating influences the fate of the plates used for osteosynthesis within the human organism, in regard to the possible need for their removal. During a 5-year period, 108 of 1,396 plates coated with anodic titanium oxide had to be removed for various reasons: plate exposure (47), osteomyelitis (25), palpable swelling and tenderness (21), patient request for psychological reasons (13), or fracture of the plate (2). In none of these 108 cases was metallosis observed, which otherwise is reported relatively frequently in the vicinity of traditional titanium fixing elements, nor was any tissue damage connected with the surface of the plates. The results indicate the favorable properties of the titanium oxide ceramic surface.     

Glow discharge plasma treatment of titanium plates enhances adhesion of osteoblast-like cells to the plates through the integrin-mediated mechanism

PURPOSE: Initial adhesion of cells to implant surfaces and subsequent behavior of the cells are important determinants for biocompatibility of the implants. It was previously reported that both adhesion of MC3T3-E1 osteoblast-ike cells to titanium (Ti) plates and their differentiation into more mature cells on the plates were stimulated by treatment of the plates with glow discharge plasma (GDP). However, the mechanisms of these processes have not yet been identified. In this study, the adhesion and differentiation mechanism of osteoblast-like cells to Ti with and without GDP were investigated. MATERIALS AND METHODS: The adhesion and differentiation mechanism of MC3T3-E1 osteoblast-like cells to Ti, with and without GDP, were investigated by cultivation in serum-free medium and use of a competitive inhibition test to examine the influence of extracellular matrix proteins contained in the serum and to identify cell binding proteins. In addition, the amount of fibronectin adsorption on each Ti plate was investigated by enzyme-linked immunosorbent assay and fluorescein isothiocyanate labeling. Furthermore, the stress fiber formation and morphology of cells on each plate were evaluated microscopically. RESULTS: Adherent cells on Ti plates, with and without GDP, were significantly reduced in serum-free conditions and the presence of RGDS (Arg-Gly-Asp-Ser) peptides. Fibronectin adsorption on titanium plates was increased by GDP. Furthermore, stress fiber formation of cells was extremely progressive on the Ti plates treated with GDP and was not observed on the cells inhibited by RGDS peptide. DISCUSSION: These results suggest that RGDS containing serum proteins have a major role in regulating specific adhesion of cells to Ti, and GDP promoted cell adhesion and differentiation on Ti by increasing the adsorption of proteins. CONCLUSION: According to this study, the adhesion and differentiation mechanism of osteoblast-like cells to Ti, with and without GDP, can be obtained.     

Comparison between resorbable plates vs. titanium plates for treatment of zygomatic fractures: a systematic review with meta-analysis

Purpose

To compare resorbable plates with titanium plates for the fixation of zygomatic fractures, taking into account postoperative complications.

Methods

This systematic review followed the guidelines of PRISMA and the recommendations of the Cochrane Handbook and was registered in PROSPERO. The electronic search was performed in the Web of Science, PubMed, Virtual Health Library, and Cochrane Library databases and in the gray literature. The study selection and the data extraction were performed by three calibrated and independent researchers. The assessment of the risk of bias in the studies was performed using the Cochrane Risk of Bias Tool for clinical trials. Meta-analyses were performed using Review Manager Software version 5.3, using the Peto’s Odds Ratios (PORs), and when I² > 30, the random effect model was used. The evaluation of the quality of the evidence was carried out through GRADE.

Results

A total of 2651 studies were screened and only nine were included; 7 of which were used for quantitative assessment. The follow-up time for patients ranged from 6 months to 5 years. All studies showed a low risk of bias in the “incomplete outcome data” domain. The need for plate removal (POR: 0.11, 95% CI: 0.02 to 0.81, I² = 0%) and dehiscence (POR 0.12, 95% CI 0.02 to 0.63, I² = not applied) was lower for the group of patients who used resorbable plates than for titanium plates.

Conclusion

There was no difference in the occurrence of infection, diplopia, or paresthesia between the fixation methods. Resorbable plates showed better postoperative clinical performance.