A Bacteria and Cell Repellent Zwitterionic Polymer Coating on Titanium Base Substrates towards Smart Implant Devices.

Biofouling and biofilm formation on implant surfaces are serious issues that more than often lead to inflammatory reactions and the necessity of lengthy post-operation treatments or the removal of the implant, thus entailing a protracted healing process. This issue may be tackled with a biocompatible polymeric coating that at the same time prevents biofouling. In this work, oxygen plasma-activated silanized titanium substrates are coated with poly(sulfobetaine methacrylate), a zwitterionic antibiofouling polymer, using photopolymerization. The characterization of polymer films includes FT-IR, AFM, and adhesion strength measurements, where adhesion strength is analyzed using a cylindrical flat punch indenter and water contact angle (WCA) measurements. Both cytotoxicity analysis with primary human fibroblasts and fluorescence microscopy with fibroblasts and plaque bacteria are also performed is this work, with each procedure including seeding on coated and control surfaces. The film morphology obtained by the AFM shows a fine structure akin to nanoropes. The coatings can resist ultrasonic and sterilization treatments. The adhesion strength properties substantially increase when the films are soaked in 0.51 M of NaCl prior to testing when compared to deionized water. The coatings are superhydrophilic with a WCA of 10° that increases to 15° after dry aging. The viability of fibroblasts in the presence of coated substrates is comparable to that of bare titanium. When in direct contact with fibroblasts or bacteria, marginal adhesion for both species occurs on coating imperfections. Because photopolymerization can easily be adapted to surface patterning, smart devices that promote both osseointegration (in non-coated areas) and prevent cell overgrowth and biofilm formation (in coated areas) demonstrate practical potential.

In vitro biocompatibility of orthodontic miniscrews with human gingival fibroblast and SAOS-2 osteoblast cultures.

PURPOSE: Miniscrews are an important choice for orthodontic anchorage. Yet reports on failures do exist, and attempts have been made to elucidate the causes. Clinical outcomes may be compromised not only by the mechanical implications of miniscrew design and the location of anchorage but also by poor biocompatibility. Hence, this study deals with the surface roughness and elemental composition of miniscrews and how these properties may affect the in vitro biocompatibility of four commercially available miniscrews. METHODS: Most of the currently available miniscrews are made of TiAl6V4, an alloy widely considered to be biocompatible. The samples tested in this study included four similarly dimensioned TiAl6V4 products from different manufacturers: tomas® by Dentaurum, OrthoEasy® by Forestadent®, Dual Top™ by Jeil Medical/Promedia, and LOMAS by Mondeal®. The surface properties of these products were characterized by scanning electron microscopy (SEM) and energy-dispersive X­ray spectroscopy (EDX). Cytotoxicity was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and agar overlay assays according to ISO 10993-5. RESULTS: The miniscrew products were found to show variations in surface-finish quality pertaining to topography and chemical composition, with the latter departing slightly from the manufacturers' specifications. MTT assays yielded rates of cell culture viability in excess of 90%, and agar overlay assays did not reveal decoloration beyond the specimen outlines in any of the experimental groups tested. CONCLUSIONS: The four miniscrew products exhibited some minor, but statistically significant, differences in microtopography, alloy composition, and biological inertness. Cytotoxicity testing revealed that all four products should be considered non-cytotoxic, thus, ruling out poor biocompatibility as a cause of miniscrew failure.

Correlation of general and oral health-related quality of life in malocclusion patients treated with a combined orthodontic and maxillofacial surgical approach.

PURPOSE: The aim of the study was to collect information about the oral health-related quality of life (OHRQoL) after combined orthodontic and maxillofacial surgical treatment as well as its influence on health-related quality of life (HRQoL). MATERIALS AND METHODS: The study includes data from a total of 130 subjects, 65 of whom (21 male, 44 female, mean age at baseline: 24 years, mean age at the time of surgery: 26 years) were compared with control subjects matched on the basis of gender and age. The set of questionnaires used consisted of a questionnaire advanced by the authors including 35 general and treatment-specific questions, and the German version of the validated "Orthognathic Quality of Life Questionnaire" (OQLQ) to analyze the specific OHRQoL, and the SF-36 to measure HRQoL. RESULTS: The main reason for treatment was most often a combination of esthetic and functional complaints. In most cases, the treatment results met the expectations of subjects well or very well, particularly in the areas of aesthetics and masticatory function. Postoperative numbness or paresthesia were present in 59% of patients, especially in the chin and lower lip areas. In all, 20% of subjects considered the temporary restriction of mouth opening as very bothersome. A decrease in HRQoL was noted as compared with the control group in the subscales of "role physical" (p < 0.001), "general health" (p = 0.023), and "role emotional" (p = 0.007). No differences were found in the "physical functioning," "bodily pain," "vitality," "social functioning," and "mental health" subscales. The specific OHRQoL resulted in statistically significant limitations in the patient group for all areas examined. The "oral function" (p < 0.001), "dentofacial aesthetics" (p = 0.005), "social aspects" (p = 0.002), and "awareness of dentofacial aesthetics" (p = 0.004) values were significantly decreased. CONCLUSIONS: Overall, patients expressed a high level of satisfaction and approval with regard to the combined orthodontic and maxillofacial surgical treatment. However, even after combined orthodontic and maxillofacial surgical treatment of malocclusion patients, it is possible to detect smaller limitations with regard to the specific OHRQoL, which may have a negative impact on HRQoL. Based on the results, a participatory decision-making process focusing on the individual therapy-related expectations, desires, and psychological factors of the patient concerning the improvements effected by the treatment appears to be advisable.

Oral health-related quality of life after orthodontic treatment for anterior tooth alignment: Association with emotional state and sociodemographic factors.

OBJECTIVES: The aim of this work was to evaluate associations of oral health-related quality of life (OHRQoL) with sociodemographic factors and with emotional state in adults after orthodontic treatment for anterior tooth alignment. Few studies have examined these specific associations in the past, one reason presumably being a lack of specific instruments. PATIENTS AND METHODS: A total of 128 adult patients consecutively treated with multibracket appliances were contacted during the retention period. The response rate was 68 %. They were asked to complete both an emotional well-being test (Zerssen Mood Scale, Bf-S) and a 52-item orthodontic survey of OHRQoL, which we had developed based on the German version of the Oral Health Impact Profile (OHIP-G14). RESULTS: The study demonstrated a high association of self-perceived apperance with OHRQoL and a strong role of the teeth and mouth. Aside from a few exceptions, the patients' responses in the survey did not reveal any significant gender-specific or age-specific differences. By contrast, patients in lower-than-normal spirits were found to also respond with significantly less favorable ratings to the survey items dealing with self-perceived overall attractiveness, facial attractivenss, and course of treatment. CONCLUSION: Dental appearance has a psychosocial impact on private and job-related interactions, which can increase the motivation of those affected to seek treament. Our orthodontic OHRQoL survey proved to be informative and practical. Findings that were especially striking included the patients' high acceptance of the changes induced by treatment and their high willingness to recommend such treatment to other adults.

Shear bond strength of orthodontic brackets to enamel after application of a caries infiltrant.

OBJECTIVE: To examine differences in the shear bond strength of orthodontic brackets on differently mineralized enamel surfaces after applying a caries infiltrant or conventional adhesive. MATERIALS AND METHODS: A total of 320 bovine incisors were assigned to eight pretreated groups, and the shear force required for debonding was recorded. Residual adhesive was evaluated by light microscopy using the adhesive remnant index. Statistical analysis included Kolmogorov-Smirnov, analysis of variance (ANOVA), and Scheffé tests. RESULTS: The highest bond strength (18.8 ± 4.4 MPa) was obtained after use of the caries infiltrant. More residual adhesive and fewer enamel defects were observed on infiltrated enamel surfaces. Brackets on demineralized enamel produced multiple enamel defects. CONCLUSIONS: Acceptable bond strengths were obtained with all material combinations. A caries-infiltrant applied before bracket fixation has a protective effect, especially on demineralized enamel.

Reliability of clinical symptoms in diagnosing temporomandibular joint arthritis in juvenile idiopathic arthritis.

OBJECTIVE: Temporomandibular joint (TMJ) arthritis, commonly considered oligoarthritic/asymptomatic, occurs frequently in children with juvenile idiopathic arthritis (JIA), and gadolinium-enhanced magnetic resonance imaging (Gd-MRI) has proved to be a sensitive diagnostic tool in this context. We compared the reliability of clinical examinations to Gd-MRI results in diagnosing the condition. METHODS: Patients with JIA (134 consecutive) underwent routine clinical and Gd-MRI examinations. The clinical items examined were clicking, tenderness (TMJ/adjacent muscles), and mouth-opening capacity. Blinded MRI reading focused on inflammation (synovitis/hypertrophy). After statistical power analysis, the clinical findings for 134 healthy controls were included. Contingency analysis was used to determine the sensitivity, specificity, and frequency of clinical symptoms (JIA/healthy controls); Cohen's κ was used to establish the interrater reliability. RESULTS: Statistically significant differences were observed between JIA and healthy control groups with regard to the concise screening items (power analysis > 0.95), whereas no differences in mouth-opening capacity were noted. In 80% of the patients with JIA, Gd-MRI revealed signs of TMJ arthritis, with positive correlations between concise screening items and Gd-MRI results. The average specificity was 0.81, but the sensitivity was low, at 0.42. Combining items led to a marked increase in the sensitivity (0.73). There was a high rate of both false-negative and false-positive results (corresponding to clinical underdiagnosis or overdiagnosis of TMJ arthritis). CONCLUSION: Despite a relatively high specificity, clinical examination alone does not seem sufficiently sensitive to adequately detect TMJ arthritis. Thus, a relatively high number of cases will be missed or overdiagnosed, potentially leading to undertreatment or overtreatment. Gd-MRI may support correct diagnosis, thereby helping to prevent undertreatment or overtreatment.

Effects of incorporation of nano-fluorapatite or nano-fluorohydroxyapatite on a resin-modified glass ionomer cement.

This study aimed to investigate the fluoride release properties and the effect on bond strength of two experimental adhesive cements. Synthesized particles of nano-fluorapatite (nano-FA) or nano-fluorohydroxyapatite (nano-FHA) were incorporated into a resin-modified glass ionomer cement (Fuji Ortho LC) and characterized using X-ray diffraction and scanning electron microscopy. Blocks with six different concentrations of nano-FA or nano-FHA were manufactured and their fluoride release properties evaluated by ultraviolet spectrophotometry. The unaltered glass ionomer cement Fuji Ortho LC (GC, control) and the two experimental cements with the highest fluoride release capacities (nano-FA+Fuji Ortho LC (GFA) and nano-FHA+Fuji Ortho LC (GFHA)) were used to bond composite blocks and orthodontic brackets to human enamel. After 24 h water storage all specimens were debonded, measuring the micro-tensile bond strength (µTBS) and the shear bond strength (SBS), respectively. The optimal concentration of added nano-FA and nano-FHA for maximum fluoride release was 25 wt.%, which nearly tripled fluoride release after 70 days compared with the control group. GC exhibited a significantly higher SBS than GFHA/GFA, with GFHA and GFA not differing significantly (P>0.05). The µTBS of GC and GFA were significantly higher than that of GFHA (P≤0.05). The results seem to indicate that the fluoride release properties of Fuji Ortho LC are improved by incorporating nano-FA or nano-FHA, simultaneously maintaining a clinically sufficient bond strength when nano-FA was added.

Microdamage in cortical bone due to the overtightening of orthodontic microscrews.

BACKGROUND AND AIM: The possibility of skeletal anchorage achieved with mini-implants has greatly broadened the spectrum of treatment modalities in orthodontics. Aim of this study was to investigate the microstructural alterations in cortical bone due to overtightening of orthodontic microscrews during the insertion procedure. MATERIAL AND METHODS: After having prepared three fresh pelvic porcine bone segments and removed the periosteum, we drilled 25 holes 1 mm in diameter into the segments. Using a screwdriver, we then manually inserted a total of 20 orthodontic microscrews from the Aarhus Anchorage System (1.5 mm x 7.7 mm) into the holes: ten screws were inserted about 6.7 mm deep, leaving the last 1 mm of the thread visible outside the bone. The other ten screws were initially inserted 7.7 mm (until the screw thread was no longer visible and the screw neck was slightly touching the cortex). Those last ten screws were then tightened by another quarter-turn. Five drill-holes were left empty, serving as a reference. The three pelvic bone segments were sawed into 25 smaller bone-specimens, 20 segments containing one screw and five with only the drill-hole. They were cortically cross-sectioned and processed for scanning electron microscope analysis. All the microcracks in the peri-implant bone tissue at least 50 microm long were documented for each sample. Statistical analysis was carried out according to the "number of cracks", "accumulated length of all cracks", "maximum radius of crack alteration", and "longest crack". The specimens were then divided into two subgroups according to cortical thickness. RESULTS: The group of overtightened implants showed higher values in the following categories: number of cracks, accumulated length of all cracks, maximum radius of crack alteration, and longest crack in comparison to the reference samples without screws and the group of less deeply-inserted implants. However, we identified no correlation between cortical thickness and the degree of microdamage. CONCLUSIONS: We demonstrate that there was more microstructural damage in cortical bone due to overtightening through deep insertion of orthodontic microscrews than occurred at the lower insertion depth. Extensive osseous microdamage may detract from the stability of immediately-loaded microscrews and implants due to the bone-remodeling processes initiated by microdamage. The subject of just how serious this potential risk is should be addressed in future studies.

Design of a Global Medical Database which is Searchable by Human Diagnostic Patterns.

UNLABELLED: We describe a global medical database which is designed for efficient evaluation. It allows language independent search for human diagnostic parameters. Core of the database is a fully automated electronic archive and distribution server for medical histories of real but anonymous patients which contain patterns of diagnosis, chosen treatment, and outcome. Every pattern is represented by a feature vector which is usually a sequence of numbers, and labeled by an unambiguous "pattern name" which identifies its meaning. Similarity search is always done only over patterns with the same pattern name, because these are directly comparable. Similarities of patterns are mapped to spatial similarities (small distances) of their feature vectors using an appropriate metric. This makes them searchable. Pattern names can be "owned" like today domain names. This facilitates unbureaucratic definition of patterns e.g. by manufacturers of diagnostic devices. APPLICATION: If there is a new patient with certain diagnostic patterns, it is possible to combine a part or all of them and to search in the database for completed histories of patients with similar patterns to find the best treatment. Confinement of the result by conventional language based search terms is possible, and immediate individual statistics or regression analyses can quantify probabilities of success in case of different treatment choices. CONCLUSIONS: Efficient searching with diagnostic patterns is technically feasible. Labeled feature vectors induce a systematic and expandable approach. The database also allows immediate calculation of individual up to date prediction models.

Human gingival fibroblast response to electropolished NiTi surfaces.

In the present study the in vitro biocompatibility of electropolished NiTi sheets is investigated. The assessment of cytotoxic effects due to potential Ni leaching from metal sheets was performed in direct contact with primary human fibroblast cultures using the 5-bromo-2'-deoxyuridine cell proliferation assay and morphologic studies via light microscopy and scanning electron microscopy. To assess toxic effects related to Ni-ions release, cells cultured in the presence of increasing concentrations of Ni(2+) (NiSO(4).6H(2)O) served as positive controls. It is shown that while the addition of NiSO(4) caused severe proliferation decrease (approximately 80%) and morphologic damage at a concentration of 50 mg/L Ni(2+) no negative effects were observed in fibroblasts cultured in the presence of electropolished NiTi sheets. The results are discussed in terms of surface topography effects on the biocompatibility of NiTi shape memory alloys.

Assessing the biocompatibility of NiTi shape memory alloys used for medical applications.

The present paper reviews aspects related to the biocompatibility of NiTi shape memory alloys used for medical applications. These smart metallic materials, which are characterised by outstanding mechanical properties, have been gaining increasing importance over the last two decades in many minimal invasive surgery and diagnostic applications, as well as for other uses, such as in orthodontic appliances. Due to the presence of high amounts of Ni, the cytotoxicity of such alloys is under scrutiny. In this review paper we analyse work published on the biocompatibility of NiTi alloys, considering aspects related to: (1) corrosion properties and the different methods used to test them, as well as specimen surface states; (2) biocompatibility tests in vitro and in vivo; (3) the release of Ni ions. It is shown that NiTi shape memory alloys are generally characterised by good corrosion properties, in most cases superior to those of conventional stainless steel or Co-Cr-Mo-based biomedical materials. The majority of biocompatibility studies suggest that these alloys have low cytotoxicity (both in vitro and in vivo) as well as low genotoxicity. The release of Ni ions depends on the surface state and the surface chemistry. Smooth surfaces with well-controlled structures and chemistries of the outermost protective TiO2 layer lead to negligible release of Ni ions, with concentrations below the normal human daily intake.

Transformation behavior, chemical composition, surface topography and bending properties of five selected 0.016" x 0.022" NiTi archwires.

PURPOSE: The aim of this study was to characterize five selected commercial NiTi archwires in terms of their transformation behavior, chemical composition, surface topography and mechanical properties (at temperatures of 22 degrees C, 37 degrees C and 60 degrees C). MATERIAL AND METHODS: The rectangular orthodontic archwires investigated were Neo Sentalloy F80 (GAC, Central Islip, NY, USA), 35 degrees C Thermo-Active Copper NiTi (A-Company/Ormco, Glendora, CA, USA), Rematitan "Lite" (Dentaurum, Pforzheim, Germany), Titanol SE S (Forestadent, Pforzheim, Germany) and Titanal (Lancer, San Marcos, CA, USA) in size 0.016" x 0.022". The chemical composition and surface topography were analyzed by energy dispersive X-ray spectroscopy using an analytical scanning electron microscope (XL30, EDAX SUTW Saphire Detector; Philips, Eindhoven, Netherlands). The transition temperatures were measured by means of differential scanning calorimetry (DSC; Perkin-Elmer Pyris 1, Perkin-Elmer, Fremont, CA, USA) in a range of - 80 degrees C to + 80 degrees C. The mechanical properties and their dependence on temperature were determined by means of 3-point bending tests. The binary archwire materials were characterized by a two-phase structure (NiTi matrix and Ni3Ti4 precipitates). RESULTS: The SEM analyses revealed abradant residues in virtually all archwires, while DSC revealed complex transformation properties. In addition to the martensitic and austenitic transformations, an R-phase transformation was also detected. The bending tests showed pronounced loading and unloading plateaus. The martensitic archwires (Neo Sentalloy F80, 35 degrees C Thermo-Active Copper NiTi) were found to have a lower strength than the martensitic-austenitic (Rematitan "Lite") and the austenitic archwires (Titanol SE S, Titanal). With increasing temperature (in the range from 22 degrees C to 60 degrees C) a linear rise in the plateau forces was recorded. CONCLUSIONS: When assessing the quality of archwires, account should be taken of the surface quality, as it is this that determines corrosion resistance, biocompatibility and friction characteristics. The mechanical properties depend on the initial state; moderate plateau forces and plateau moments can only be achieved with martensitic archwires. In contrast to conventional steel alloys, the strength characteristics are heavily dependent on temperature and need to be known if NiTi archwires are to be used to optimal effect. In addition, the superelastic plateau is used only partially, if at all, when minimum leveling is required.

On the in vitro biocompatibility of Elgiloy, a co-based alloy, compared to two titanium alloys.

AIM: The aim of the present investigation was to contribute to an understanding of the effects of surface topography and chemical composition on the corrosion behavior and thus the biocompatibility of Elgiloy (RMO, Denver, CO, USA), a common Co-based alloy. MATERIAL AND METHODS: The results are compared with those obtained for a binary NiTi alloy, Neo Sentalloy (GAC, Central Islip, NY, USA) and a beta-III-Ti alloy, TMA (Ormco, Glendora, CA, USA). In the present study, the surface topography and the chemical composition of two different grades of Elgiloy, Blue Elgiloy (soft) and Yellow Elgiloy (ductile), were examined by means of scanning electron microscopy (SEM) and energy-dispersive spectroscopy analysis (EDS). Their corrosion behavior in half-strength Ringer solution and in an artificial saliva solution according to Barrett [1] was investigated using potentiodynamic corrosion testing (PDC). The photometry-based PAN method was used to quantify the released Ni and Co ions. The in vitro biocompatibility of the two grades of Elgiloy was tested in three different cell cultures: in L929, a commercially available mouse fibroblast cell line, and in primary human epithelial cells and fibroblasts. RESULTS: The results of the corrosion testing showed satisfactorily high pitting corrosion potentials but lower repassivation potentials and a strong increase in current density once pitting had occurred. The photometric results revealed the release of Ni and Co ions in both tested electrolytes. The tested native surfaces exhibited numerous grinding and polishing grooves, inclusions and inhomogeneities of the microstructure. After corrosion testing the same surfaces displayed numerous signs of corrosion, especially in areas with microstructural inhomogeneities. In vitro biocompatibility testing showed a substantially reduced dehydrogenase activity in the presence of Elgiloy. The reduced quality of surface finish resulting from the manufacturing process led in the case of the tested Elgiloy types to decreased corrosion resistance with consequently reduced in vitro biocompatibility. CONCLUSIONS: In this context it is also conceivable that patients with a proven allergy to nickel, cobalt or chromium may react sensitively to the deployment of this alloy, at least in the surface quality tested by us. From this aspect, the introduction of a binding standard for the surface quality of materials used in orthodontic appliances is urgently recommended.

On the interaction of polyacrylic acid as a conditioning agent with bovine enamel.

In the present paper, the effects of polyacrylic acid (PAA) conditioning on the morphology and chemistry of bovine enamel surface and the resulting interfacial reactions are being investigated using photometric, microscopic (SEM, AFM), electron spectroscopic (XPS) and staining methods (neutral red dye). The results are compared to two reference surfaces obtained by simple grinding and by etching with a phosphoric acid solution. It is shown that PAA conditioning leads to the leaching of calcium and phosphorus ions, to the smoothening of the surface and probably to the formation of a polymeric film at the surface. A mechanism by which a preliminary PAA conditioning of the enamel leads to the reported higher bonding strength between enamel and glass ionomer cements is proposed.

On the properties of two binary NiTi shape memory alloys. Effects of surface finish on the corrosion behaviour and in vitro biocompatibility.

The present paper compares the transformation behaviour and mechanical properties of two orthodontic wires of close chemical compositions. The effects of surface topography and surface finish residues on the potentiodynamic corrosion behaviour and biocompatibility are also reported. The cytotoxicity tests were performed on both alloys in fibroblast cell cultures from human gingiva using the MTT test. It is shown that the surface finish and the amounts of surface finish residues affect dramatically the corrosion resistance. Bad surface finish results in lower corrosion resistance. The in vitro biocompatibility, though not affected to the extent of corrosion resistance, is also reduced as the surface roughness and the amounts of residues increase. This is thought to be due to surface effects on corrosion and metallic ions release.