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PubMed2004

Characterization and cytotoxicity of ions released from stainless steel and nickel-titanium orthodontic alloys.

The purpose of this study was to qualitatively and quantitatively characterize the substances released from orthodontic brackets and nickel-titanium wires and to comparatively assess the cytotoxicity of the ions released from these orthodontic alloys. Two full sets of stainless steel brackets of 20 brackets each (weight 2.1 g) and 2 groups of 0.018 x 0.025 Ni-Ti archwires of 10 wires each (weight 2.0 g) were immersed in 0.9% saline solution for a month. The immersion media were analyzed with inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and the ionic content was statistically analyzed with 1-way analysis of variance (ANOVA). Human periodontal ligament fibroblasts and gingival fibroblasts were exposed to various concentrations of the 2 immersion media; nickel chloride was used as a positive control for comparison purposes. The cytotoxic or cytostatic activity of the media was investigated with the MTT and the DNA synthesis assays. The results of the cytotoxicity assay were analyzed with 2-way ANOVA and the Tukey test with solution and concentration variants as discriminating variables (alpha=0.05). The results indicated no ionic release for the nickel-titanium alloy aging solution, whereas measurable nickel and traces of chromium were found in the stainless steel bracket-aging medium. Concentrations of the nickel chloride solution greater then 2 mM were found to reduce by more than 50% the viability and DNA synthesis of fibroblasts; however, neither orthodontic materials-derived media had any effect on the survival and DNA synthesis of either cells.

Adult↗
PubMed2005

Effect of 0.4% stannous fluoride gel on Streptococci mutans in relation to elastomeric rings and steel ligatures in orthodontic patients.

BACKGROUND: Patients with fixed orthodontic appliances often experience an absolute increase in the number of Streptococci mutans colony-forming units (cfu). The aim of this investigation was to study the development of biofilm and S. mutans cfu in connection with stainless steel ligatures and elastomeric rings in orthodontic patients treated with and without 0.4% stannous fluoride gel (SFG). MATERIAL: Forty-seven patients were divided into 2 groups: those treated with 0.4% SFG for 4 minutes (experimental) and those without 0.4% SFG (control). In each patient, elastomeric rings were used for ligation on 1 side of the dental arch midline, and stainless steel ligatures were used on the opposite side. Saliva samples were collected before and after appliance placement. At 15 and 30 days after appliance placement, biofilm samples from the stainless steel ligatures and the elastomeric rings were collected and subjected to microbiologic procedures and scanning electron microscopy (SEM) analysis. RESULTS: The numbers of S. mutans cfu in the saliva and biofilm were not statistically different between the teeth fitted with elastomeric rings and stainless steel ligatures, or between the experimental and control groups. SEM analysis showed biofilm formation on both ligature ties. CONCLUSIONS: Topical application of 0.4% SFG in orthodontic patients with elastomeric rings or stainless steel ligatures does not cause a significant decrease in S. mutans cfu in the saliva and biofilm.

Adolescent↗
PubMed2005

Treatment outcomes in 4 modes of orthodontic practice.

BACKGROUND: This study is a continuation of a previously published report on the outcome of orthodontic treatment provided in offices representing different modes of practice. METHODS: The sample consisted of duplicate pretreatment (T1) and posttreatment (T2) dental casts of 348 patients from traditional private orthodontic practices (5 offices, 134 patients), company-owned practices (5 offices, 107 patients), offices associated with practice-management organizations (2 offices, 60 patients), and general dental practices (2 offices, 47 patients). Methods were used to obtain random, representative samples from each office, starting with lists of patients who were treated consecutively with full fixed orthodontic appliances. The dental casts were measured by 2 independent judges who used the unweighted PAR score. RESULTS: Good interjudge agreement was shown on the initial casts, but the agreement was not as strong on the final casts. CONCLUSIONS: The measurements showed that treatment outcomes were generally satisfactory, although some significant differences between offices and management modes were shown.

Adolescent↗
PubMed2006

Comparison of frictional resistance after immersion of metal brackets and orthodontic wires in a fluoride-containing prophylactic agent.

INTRODUCTION: In this study, we investigated and compared the levels of frictional resistance between metal brackets and orthodontic wires after immersion in an acidified phosphate fluoride (APF) agent. METHODS: Three types of mandibular incisor stainless steel metal brackets with beta-titanium alloy wire (TMA), heat-activated nickel-titanium wire (Ni-Ti), and 2 sizes of stainless steel wires (SSW) were immersed in 0.2% APF and pH 6.75 artificial saliva solutions for 24 hours. The study included 480 bracket-wire specimens. The frictional resistance was measured on an EZ-test machine (Shimadazu, Tokyo, Japan) with a 5-N load cell. An Alastik (Quik-Stik Clear, A-1 Alastik, 3M Unitek, Monrovia, Calif) module ligated to the bracket was attached to the crosshead of the machine and pulled at a speed of 10 mm per minute for a distance of 5 mm. A completely randomized 1-way ANOVA was used to test for significant differences among the 3 bracket/wire specimens after immersion in 0.2% APF and pH 6.75 artificial saliva solutions. This was followed by the Student-Newman-Keuls multiple comparison of means ranking at P <.05 to determine differences between the groups. RESULTS: In the APF-immersed group, the static frictional force was greater than the kinetic frictional force. The frictional forces of the orthodontic wires had statistically significant differences (P <.05) in this progressive order: TMA, Ni-Ti, and SSW. Similar frictional force results were obtained in the pH 6.75 saliva group (P <.05). The frictional force values of the APF group were higher than those of the pH 6.75 saliva group (P <.05). CONCLUSIONS: This study demonstrates that the frictional forces of orthodontic brackets and wires are influenced by contact with fluoride-containing solutions.

Acidulated Phosphate Fluoride↗
PubMed2006

A comparison of the shear-peel and third-order bond strengths of orthodontic brackets with 2 etch techniques and the role of bracket asymmetry.

INTRODUCTION: Innovations in orthodontic bonding are inevitably followed by a flurry of studies to ascertain efficacy. Unfortunately, the published reports are often contradictory or highly variable. The primary purpose of this study was to analyze protocols that measure orthodontic bracket bond strength. The effects of loading mode and the role of bracket asymmetry were examined. The secondary goal was to test a self-etch enamel preparation system. MATERIALS AND METHODS: Flattened stainless steel orthodontic brackets (.022-in Victory Series, 3M Unitek, Monrovia, Calif) were bonded to a total of 192 flattened bovine incisors with a resin composite bonding agent (Transbond XT, 3M Unitek.) The enamel was prepared with traditional, two-step (TS) acid (37% phosphoric acid gel) etching and priming (Transbond XT Primer, 3M Unitek) or with a single step (SS) self-etch (Transbond Plus, 3M Unitek) material. Cement thickness was held constant and bonding was done under controlled temperature and humidity. The brackets were debonded in the occlusogingival and in the gingivocclusal directions (ie, the 2 senses of shear-peel) and using a new technique in the buccal-root and in the lingual-root directions (ie, the 2 senses of a third-order moment.) RESULTS: Data showed no significant differences between TS and SS regardless of load modality. However, significant differences were revealed between the senses of debonding, indicating bracket asymmetry effects. CONCLUSIONS: The wide clinical use of these newer self-etching primers has been supported by these limited findings. A new third-order debonding protocol has been demonstrated to be a useful tool. Bracket asymmetry affects some bond strength values, and there is a need for standardization of testing protocols.

Acid Etching, Dental↗
PubMed2005

The effect of surface treatment and clinical use on friction in NiTi orthodontic wires.

OBJECTIVES: Since the low friction of NiTi wires allows a rapid and efficient orthodontic tooth movement, the aim of this research was to investigate the friction and surface roughness of different commercially available superelastic NiTi wires before and after clinical use. The surface of all of the wires had been pre-treated by the manufacturer. MATERIALS: Forty superelastic wires (Titanol Low Force, Titanol Low Force River Finish Gold, Neo Sentalloy, Neo Sentalloy Ionguard) of diameter 0.016 x 0.022 in. were tested. The friction for each type of NiTi archwire ligated into a commercial stainless steel bracket was determined with a universal testing machine. Having ligated the wire into the bracket, it could then be moved forward and backwards along a fixed archwire whilst a torquing moment was applied. The surface roughness was investigated using a profilometric measuring device on defined areas of the wire. Statistical data analysis was conducted by means of the Wilcoxon test. RESULTS: The results showed that initially, the surface treated wires demonstrated significantly (p < 0.01) less friction than the non-treated wires. The surface roughness showed no significant difference between the treated and the non-treated surfaces of the wires. All 40 wires however showed a significant increase in friction and surface roughness during clinical use. SIGNIFICANCE: Whilst the Titanol Low Force River Finish Gold (Forestadent, Pforzheim, Germany) wires showed the least friction of all the samples and consequently should be more conservative on anchorage, the increase in friction of all the surface treated wires during orthodontic treatment almost cancels out this initial effect on friction. It is therefore recommended that surface treated NiTi orthodontic archwires should only be used once.

Dental Alloys↗
PubMed2004

Dental CT and orthodontic implants: imaging technique and assessment of available bone volume in the hard palate.

PURPOSE: Palatal implants (PI) have been introduced for orthodontic treatment of dental and skeletal dysgnathia. Due to the restricted amount of bone in this region, precise preoperative anatomic information is necessary. The aim of this study was to determine whether dental CT could serve as a tool to locate the optimal size and position for orthodontic implant placement. MATERIALS AND METHODS: In 32 patients, where palatal implant placement was planned, axial CT scans of the maxillary bone were acquired. Using a standard dental software package (Easy Vision dental software package 2.1, Philips; Best, The Netherlands), paracoronal views were reconstructed and measurements of palatal bone height in 3 mm increments, dorsally from the incisive canal, were performed in the median and both paramedian regions. RESULTS: The overall mean bone height was 5.01 mm (S.D. 2.60), ranging from 0 to 16.9 mm. The maximum palatal bone height was 6.17 mm (S.D. 2.81) at 6 mm dorsally from the incisive canal. Due to the lack of adequate bone (less than 4 mm), implant placement was not performed in 3 cases (7%). In the remaining 39 cases (93.0%), primary implant stability was achieved and complications, such as perforation of the palate, could be avoided. CONCLUSION: The results demonstrate that dental CT promises to be a valuable tool in evaluating the potential and optimal size and site for orthodontic implant placement.

Adolescent↗
PubMed1983

Toothbrush pressures of orthodontic patients.

The intention of this study was to determine whether toothbrushing pressures varied significantly between groups of orthodontic patients who were good toothbrushers and those who were poor toothbrushers. Seventy-two patients undergoing full-banded orthodontic treatment were selected from the author's practice and were subjectively paired by him according to their habitual oral hygiene. One group of thirty-six patients who habitually displayed poor oral hygiene was compared to a group of thirty-six patients who habitually displayed good oral hygiene. A specially designed strain gauge with a force-averaging feedback mechanism was attached to each patient's manual toothbrush, and the force with which that patient brushed was averaged and recorded in pounds. The poor brushers averaged 0.20 pound, whereas the average pressure of the good brushers was 0.89 pound. The statistical evidence indicates that the difference between the two groups is highly significant and is unlikely to be due to chance alone. This study has shown that toothbrush pressures can be easily and accurately measured. The attempt to objectify a single characteristic of toothbrushing behavior in an orthodontic population is an effort to avoid the medical model explanation of behavior vis-a-vis the nonspecific and subjective word attitude. Future studies will determine whether poor toothbrushers can be changed into good toothbrushers through the progressive acquisition of greater toothbrushing forces.

Humans↗
PubMed1997

Prosthodontic considerations when using implants for orthodontic anchorage.

STATEMENT OF PROBLEM: The use of implants for orthodontic anchorage can produce superior preprosthetic tooth positions. Their use often requires a crown or prosthesis to be fabricated for use as a connection between the orthodontic devices and the implant. PURPOSE: In this article, factors that affect the design of prostheses required for orthodontic movement and examples of prosthesis designs and materials, based on the authors' experience, are presented.

Dental Implantation, Endosseous↗
PubMedDate not supplied

Shear bond strengths produced by composite and compomer light cured orthodontic adhesives.

OBJECTIVES: To test the shear bond strengths obtained when orthodontic brackets were bonded ex vivo using a composite resin and a compomer orthodontic adhesive. METHODS: Specimens were tested in a special jig made to fit an Instron testing machine. After debonding, the adhesive remaining on bracket bases and enamel surfaces was mapped. RESULTS: Bond strengths ranged from 8 to 23 MPa with the composite resin producing higher strengths than the compomer for similar combinations of variables. Bond strength was increased by longer curing and a longer debond interval and was higher for brackets with mesh bases than undercut bases. More compomer remained on the enamel surface after debonding than did the composite resin. CONCLUSION: The compomer produced bond strengths within the range considered to be clinically acceptable in other studies. If it was clinically successful as an orthodontic adhesive a compomer would confer the advantage that fluoride release would help to minimize the onset of early caries around bonded brackets.

Acrylic Resins↗
PubMed2003

The influence of orthodontic bracket base design on shear bond strength.

Many bracket base designs and adhesive materials are in clinical use today. Bases have evolved from perforated metal bases to the present foil mesh bases, and treatments range from none, to spraying metal alloy onto the base, to the most common treatment of microetching. The purpose of this study was to determine the effect of orthodontic bracket base design on mean shear bond strength 1 hour or 24 hours after bonding. For each time group, 12 specimens of 6 types of metal brackets were bonded to bovine incisors with Transbond XT (3M Unitek, Monrovia, Calif) light-cured composite resin. Brackets were debonded 1 hour or 24 hours later, and the shear bond strength was recorded. Six debonded brackets of each type from each time group were selected at random and sandblasted. All the teeth were cleaned, and half were rebonded with used brackets, and half were rebonded with new brackets. Bond strength was measured again, 1 hour or 24 hours later. Representative specimens were inspected under the scanning electron microscope. Bracket base design significantly affected mean shear bond strength. Speed (60-gauge, microetched foil-mesh base; Strite Industries, Cambridge, Ontario, Canada) had the highest bond strength at 1 hour; followed by Time (machined, integral, microetched base with mechanical undercuts; American Orthodontics, Sheboygan, Wis); American Master Series (80-gauge foil-mesh base; American Orthodontics); Ovation Roth (80-gauge layered onto 150-gauge, microetched foil-mesh base; GAC, Central Islip, NY); Orthos Optimesh XRT (100-gauge microetched foil-mesh base; Ormco, Orange, Calif); and, finally, the nickel-free brackets (injection molded, 100-gauge, microetched, foil-mesh base; World Class Technology, McMinnville, Ore). The 24-hour results were similar except that Time had the highest mean shear bond strength (ANOVA, P <.05). Chairside sandblasting significantly affected the 1-hour, but not the 24-hour, mean shear bond strengths (ANOVA, P <.05). Sandblasting appears to be an effective method of cleaning bracket bases before rebonding.

Acid Etching, Dental↗
PubMed1990

An American Board of Orthodontics case report. A nonsurgical and nonextraction approach in the treatment of a skeletal and dental Class III malocclusion in a growing patient.

This case report is presented following the specifications of the American Board of Orthodontics. The patient had a true maxillary retrognathism, a mandibular prognathism, and a lower anterior height deficiency. She was treated with a fixed orthopedic appliance, fixed orthodontic appliances, and intermaxillary elastics. [This case was presented to the American Board of Orthodontics in partial fulfillment of the requirement for the certification process conducted by the Board.

Activator Appliances↗
PubMed1998

International comparisons of professional assessments in orthodontics: Part 1--Treatment need.

An international survey has been undertaken to assess variation in professional assessment of orthodontic treatment need. Ninety-seven orthodontists from nine countries examined a standard sample of 240 dental study casts to judge the need for orthodontic treatment in terms of dental health, dental esthetics, and deviation from normal. Participants also indicated their assessment of treatment complexity and whether they would recommend treatment. Practitioners' subjective assessments were found to be only moderately reliable overall. Of the cases examined, 76% [corrected] obtained a consensus of 80% or greater on the need for treatment. Logistic regression equations were derived to explain the observed variation in treatment decisions. It was found that occlusal traits from the dental casts were highly predictive of the treatment decision, and that the practitioners' country of origin and payment methods are important influences on prescribing behavior. The treatment decisions were predicted with an accuracy of 84% by using occlusal score values for the dental esthetics, the degree of upper arch crowding, the presence of crossbite, the anterior overbite, and the buccal segment sagittal relationship. It is suggested that these traits may form the basis for an internationally validated index of treatment need for use in clinical audit and orthodontic research.

Adult↗
PubMed1999

An evaluation of factors affecting duration of orthodontic treatment.

One of the first questions asked by new orthodontic patients is: How long will I need to wear my braces? A multitude of factors have the potential to influence the answer to this question. The purpose of this retrospective study was to identify some of the primary factors that influence orthodontic treatment duration. Few studies have attempted to evaluate these factors. Data were gathered from 140 consecutively completed, comprehensive treatment patient records in five orthodontic offices. Thirty-one variables related to patient characteristics, diagnostic factors, modality of treatment, and patient cooperation were evaluated. Average treatment time was 28.6 months with a range of 23.4 to 33.4 months among the five offices. Nearly half (46.9%) of the variation in treatment duration was explained by a five-step multiple regression analysis. Included in the regression equation were the number of missed appointments, the number of replaced brackets and bands, the number of treatment phases, the number of negative chart entries regarding oral hygiene, and the prescription of headgear wear during treatment. An additional 6.7% of the variance was explained by variation among the five offices. Six of the 31 variables examined made a statistically significant (alpha =.01) contribution to the explanation of variation in treatment time. The quality of the finished cases and the appropriateness of the original diagnosis and treatment plan were not evaluated. Developing an objective assessment to evaluate these areas may be important for increasing our understanding of treatment time variation.

Adolescent↗
PubMed1999

A retrospective study of Angle Class I malocclusions treated orthodontically without extractions using two palatal expansion methods.

The correction and relapse of mandibular anterior crowding was evaluated in a population of 58 patients with Angle Class I malocclusion who were treated orthodontically without extraction of permanent teeth. The subjects were retrospectively evaluated from records taken before treatment, posttreatment, and postretention. The postretention period averaged 8 years (minimum of 4 and maximum of 20 years). All cases in Groups A and B were given orthopedic treatment to develop the maxillary apical base in the transverse and anteroposterior planes. Group A was treated with expansion of the inner bow of the face bow appliance (Kloehn), and Group B was treated with the Haas palatal expansion appliance. Both groups were then treated orthodontically with tandem mechanics. The response variables measured were: overbite, overjet, intercanine distance, intermolar distance, and irregularity index. Study groups A and B were not significantly different for subject age, retention, or postretention time. Moreover, the groups did not show significant difference for any of the response variables before treatment. However, there was a statistically significant difference in the treatment times (P =.0133). A statistically significant treatment effect was observed for most response variables in the groups. Overbite, overjet, and irregularity index were significantly reduced, intermolar distance was significantly increased, and intercanine distance showed no significant change in Groups A and B. In the postretention period, there was a tendency for variables to change slightly toward their before treatment values but no compromise of orthodontic correction was noted. The irregularity index in Group A was corrected from 4.8 to 1.1 mm and remained at 1.1 mm in the postretention period. The irregularity index in Group B was corrected from 5.1 to 1.2 mm (P =.0001) and changed slightly from 1. 2 to 1.7 mm (P =.0540) in the postretention period. We concluded that mandibular incisors tended to become more crowded postretention. However, in contrast to previous reports, we calculate this relapse to be small. Neither before treatment nor posttreatment variables were predictive of relapse.

Adolescent↗
PubMed1989

Orthodontic treatment in adults with cleft lip and palate.

A conventional orthodontic treatment method for typical malocclusions of adult patients will be described. Over 100 patients have undergone this treatment during the last decade in our cleft centre. The method involves four stages: I) orthodontics, expansion of the upper dental arch with modified quad-helix and edge-wise appliances and alignment of the teeth; II) bone grafting and closure of the oronasal fistula; III) prosthodontics, bridgework in the upper dental arch; IV) soft tissue correction of the lip and nose. The method is easy, cheap, safe and rapid enough if the forces of the quad-helix appliance are modified individually. The orthodontic, surgical and prosthodontic treatment result in a permanently balanced dental occlusion.

Adult↗
PubMed1996

Clinical implications of recent orthodontic-periodontic research findings.

During the past 15 years, advances in basic science related to periodontal biology, and clinical trials on prevention and treatment of periodontal disease, have dramatically changed many treatment concepts in periodontics. The most pertinent information for orthodontic practice from these studies is summarized. Also, recent advances in orthodontics, particularly regarding bonding of attachments to artificial tooth surfaces and improved long-term stabilization of orthodontic treatment results in adults by means of bonded lingual retainers have significant implications. This article outlines how recent research information from both dental specialties may be used by orthodontists to improve treatment planning, clinical management, and retention of their adult and elderly patients in whom different malocclusions are complicated by moderate to advanced periodontal destruction.

Adult↗
PubMed1996

Orthodontic management of the short face patient.

A short lower face may accompany various types of malocclusions depending on the structural etiology. Because most cephalometric analyses focus on the anteroposterior plane of space, they are often insufficient in diagnosing a significant vertical dysplasia. This article describes a cephalometric analysis that examines not only the vertical proportions of the face, but the various anatomical features that contribute to the dysplasia. Diagnosis is further enhanced by evaluating the facial profile with the mandible postured at various amounts of opening, suggesting the degree of vertical discrepancy. Traditional orthodontic therapy corrects the associated malocclusion but is usually ineffective in changing inherent facial proportions. However, several orthopedic methods have shown the ability to increase lower facial height when used in combination with nonextraction orthodontic mechanotherapy. Adults with short faces require a combination of orthodontics and orthognathic surgery. The Class II malocclusion can usually be managed by surgically advancing the mandible with the curve of Spee maintained. In cases of vertical maxillary deficiency, the LeFort I osteotomy with inferior repositioning provides the spatial correction that is needed. Two cases are presented to illustrate the cephalometric and facial analyses used in diagnosis, as well as the common surgical procedures to manage the short face patient.

Adult↗