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PubMed1988

Orthodontic appliances and enamel demineralization. Part 1. Lesion development.

A clinical trial was conducted to investigate carious lesion development associated with fixed orthodontic therapy. Specially designed orthodontic bands for plaque accumulation were attached to premolars scheduled to be extracted as part of an orthodontic treatment. Visible white spot lesions were seen within 4 weeks in the absence of any fluoride supplementation. Both microradiographic and SEM examinations showed surface softening of the enamel surface--that is, a surface layer was not seen in the lesions. The clinical significance of the present study is that enamel demineralization associated with fixed orthodontic therapy is an extremely rapid process caused by a high and continuous cariogenic challenge in the plaque developed around brackets and underneath ill-fitting bands. Careful inspection of the appliance at every visit and preventive fluoride programs are therefore required.

Adolescent↗
PubMed1989

Bond strength and durability of glass ionomer cements used as bonding agents in the placement of orthodontic brackets.

One potential risk of orthodontic treatment is the development of surface decalcification in association with use of brackets and bands. A bonding agent that could render tooth structure more resistant to the caries process clearly would reduce the negative iatrogenic outcomes of orthodontic therapy and thereby benefit the patient. Glass ionomer cement (GIC) bonds chemically to both enamel and dentin. In addition its high fluoride content makes enamel more resistant to caries. The purpose of this study was to evaluate the bond strength and durability of GIC when used as a bonding agent in the placement of orthodontic brackets. The materials tested were three GICs (Ketac-Fil, Ketac-Cem, and Chelon) and a standard bonding agent currently in widespread use (Rely-A-Bond). Brackets were attached to the facial surface of 96 premolar specimens and half the specimens for each bonding agent were thermocycled. Bond shear strength was determined with an Instron testing device by applying a load to the occlusal margin of each bracket to the point of failure. A two-way ANOVA indicated a significant bonding agent by thermocycling interaction (F = 4.78, p less than 0.01). Thermocycling decreased bond strength significantly for all materials, but had the greatest impact on Rely-A-Bond. However, Rely-A-Bond provided the strongest bond with and without thermocycling. Although bond strength for the standard orthodontic bonding agent deteriorates significantly under thermal stress, these results suggest that it is still greater than the bond strength provided by GIC materials.

Dental Bonding↗
PubMed1989

A review of clinical research in orthodontics.

The orthodontic journals should provide valid and reliable information that helps clinicians make appropriate decisions about patient care. The nature of the published literature has not been categorized. The American Journal of Orthodontics and Dentofacial Orthopedics (formerly the American Journal of Orthodontics) was reviewed for the years 1976, 1981, and 1986, to determine the frequency of clinical articles, the topics reported, the study designs used to obtain information, the senior author affiliation, and the major funding sources. This review demonstrates that more than half the articles in this Journal report data on patients, with the majority focusing on the evaluation or description of therapeutic interventions. Academic institutions contribute the majority of the clinical research, although only a few student theses are published. The major support for this work continues to be from departmental resources with little external funding. Despite the introduction of powerful research designs such as randomized clinical trials, these methods have not been widely adopted for orthodontic clinical research. The case report (study containing fewer than 10 patients with no control nor comparison group) continues to be the most frequently published format. Clinicians should become aware of the inherent weakness in the research designs generally used and recognize the limited information that can be obtained from such methods. Support for this research needs to be greatly expanded if the more powerful type of study required to provide valid and reliable clinical information is to be continued.

Epidemiologic Methods↗
PubMed1990

The effects of orthodontic forces on the mechanical properties of the periodontal ligament in the rat maxillary molars.

Previous studies have shown that the mechanical strength of the periodontal ligament decreased markedly after the application of an orthodontic force to the rat mandibular first molar. However, the effects of orthodontic forces on the mechanical properties of the periodontal ligament of the other teeth in the same dental arch have not been examined. Furthermore, a detailed analysis of the mechanical parameters has not been made. The purpose of the present study was to analyze mechanical parameters such as maximum shear load, maximum deformation, elastic stiffness, and failure energy in shear, estimated from the load-deformation curves obtained by extracting the rat maxillary molars from their sockets after application of an orthodontic force for 5 days. It was found that the mechanical properties of the periodontal ligament of the rat maxillary molars varied considerably among control teeth in the same dental arch. Decreases in the mechanical properties of the periodontal ligament of the experimental teeth were greatest in the first, less in the second, and least in the third molars. Significant correlations were found between the maximum load and the failure energy and between the maximum deformation and the failure energy in all teeth. It was concluded that orthodontic force affected not only the mechanical properties of the periodontal ligament of the teeth to which the force had been applied but also the mechanical properties of distant teeth.

Animals↗
PubMed1990

Radiographic materials, methods, and film-ordering patterns among orthodontic educators and private practitioners.

Orthodontic private practitioners and training institutions were surveyed in regard to the various radiographic materials and methods used in their practices and for ascertaining film-ordering patterns for various types of patients. The reasons for the survey were to assess the degree of acceptance of more radiation-efficient imaging systems into orthodontic practice and to add to the data on orthodontic patient selection criteria and radiographic prescription patterns. All orthodontic programs in the United States and Canada were surveyed, along with all of the practicing orthodontists in the state of North Carolina. The response rates were 61% and 55%, respectively. It was found that a majority of practitioners and training institutions used more radiation-efficient rare earth screen systems, but more institutions used prepatient soft-tissue enhancement beam alteration methods, thus sparing thyroid dose. Lateral cephalometric and panoramic films were found to be the most frequently ordered films, and training institutions ordered more supplemental and follow-up radiographs than private practitioners. In general, patients requiring orthognathic surgery generated a greater number and variety of films than other patient types in both surveyed populations.

Canada↗
PubMed1992

Prediction of cooperation in orthodontic treatment.

A prospective study of patient cooperation with orthodontic treatment was conducted on 100 adolescent patients. Patient, parent, and orthodontist questionnaires were used at three stages of orthodontic treatment. The first was used at the initiation of treatment and the latter two at 6-month intervals. Psychosocial measures from investigators reported in orthodontic patient cooperation literature were screened for use in the present study. These measures included attitudes toward treatment, social desirability, need for approval, and need for achievement. None of the variables selected for this investigation adequately predicted cooperation of a patient in orthodontic treatment. The stepwise regression procedures indicated that inclusion of all variables accounted for 40% of the variability. Variables assessing the orthodontist's perception of orthodontist-patient relationship had the strongest association with patient compliance.

Adolescent↗
PubMed1992

Orthodontics as a risk factor for temporomandibular disorders (TMD). II.

Debate about orthodontic treatment as a risk factor for temporomandibular disorders (TMD) led to this study. This report, the second in a series, concerns findings from a longitudinal study in which 30 new orthodontic patients have been enrolled annually since 1983. The method of Helkimo was used to collect TMD data before initiation of orthodontic treatment, and at annual intervals after debanding. Treatment was by fixed edgewise appliances. Data from a pretreatment and at least one posttreatment Helkimo examination were available for 109 patients. Follow-up data were available for 92 patients in the first year after debanding, with the corresponding sample sizes declining to 56, 33, 19, 11, and 7 for the second through the sixth posttreatment years, respectively. Primary analyses involved comparison of mean scores from the Helkimo 25-point dysfunction index scale. There were no significant differences between mean pretreatment and posttreatment Helkimo scores for any of the various groupings except for small, clinically unimportant improvements seen in the 12 to 24 month subgroup of 55 patients and in the 48 to 60 month subgroup of 11 patients. With average follow-up time of about 2 years for the 109 patients, 90% had Helkimo scores that stayed the same or improved, and 10% had scores that increased or worsened from 2 to 5 Helkimo points. We conclude that the orthodontic treatment experienced by our sample was not an important etiologic factor for TMD.

Adult↗
PubMed1992

Enamel fluoride uptake from an experimental fluoride-releasing orthodontic adhesive.

The purpose of this study was to evaluate quantitatively the fluoride uptake by enamel from an experimental visible light-cured orthodontic adhesive (VP-862) based on YbF3 filler. Sixteen contralateral premolars were extracted from 10 orthodontic patients and were classified in four groups (A, B, C, D) of four buccal surfaces each. Standardized enamel areas located on these surfaces were acid etched and were subjected to the following adhesive treatments: (A) VP-862; (B) Heliosit Orthodontic; (C) Heliobond + VP 862; and (D) Heliobond + Heliosit Orthodontic. Groups B and D were used as a reference. After 9 months in vivo, the teeth were extracted and cross-sectioned, and the enamel-adhesive interfaces were studied by combined wavelength-energy dispersive electron probe microanalysis. According to the results, the cumulative fluoride uptake by enamel from the experimental adhesive was not statistically different from the fluoride detected in the reference groups. No effect of the liquid resin, Heliobond, on the fluoride uptake gradients of enamel could be differentiated.

Acrylates↗
PubMed2005

Antibacterial properties of 4 orthodontic cements.

BACKGROUND: White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. Long-lasting antibacterial properties of orthodontic cements can reduce this phenomenon. METHODS: The antibacterial properties of 4 orthodontic cements were evaluated by direct contact test (DCT) and agar diffusion test (ADT). With the DCT technique, octet specimens of glass ionomer (CX-Plus; Shofu, Kyoto, Japan), reinforced glass ionomer (GC Fuji ORTHO LC; GC Corporation, Tokyo, Japan), and 2 composite (Transbond XT and Transbond Plus; 3M Unitek, Monrovia, Calif) orthodontic cements were placed on the sidewalls of wells of a 96-microtiter plate. Streptococcus mutans cells (ca. 1 x 10(6) ) were placed on the surface of each specimen for 1 hour at 37 degrees C. Then, fresh media was added to each well, and bacterial growth was monitored for 16 hours with a temperature-controlled spectrophotometer. This was repeated on specimens aged in phosphate-buffered saline for 1 day, 1 week, and 1 month. The ADT was performed by placing specimens in wells punched in agar plates. RESULTS: Measurement of the halo in bacterial lawn after 48 hours showed that only the glass ionomer cement (CX-Plus) produced an inhibition zone (1.2 mm around the sample). Results at the DCT showed that only the reinforced glass ionomer cement (GC Fuji ORTHO LC) exhibited potent antibacterial activity, which lasted 1 week and diminished over the next 3 weeks. CONCLUSIONS: The reinforced glass ionomer cement possessed the most potent and long-lasting antibacterial activity.

Acrylic Resins↗
PubMed2005

Occlusal perceptions of children seeking orthodontic treatment: impact of ethnicity and socioeconomic status.

INTRODUCTION: With the growth of orthodontic intervention at younger ages and increased interest in improving dentofacial appearance among the general public, it is important to assess whether demand for treatment is uniform across ethnic and socioeconomic groups. METHODS: This study compared 3 groups of children who varied by location, payment source, and ethnicity. The sample consisted of 150 children in the Bronx, NY, and 100 in Seattle, Wash, who were undergoing or anticipating orthodontic treatment in publicly funded dental clinics. Ethnic minorities comprised 69% and 92%, respectively, of these groups. The third group consisted of 84 children in Seattle, Anchorage (Alaska), and Chicago who had sought treatment by private practitioners; ethnic minorities comprised 22% of this group. Data were collected from children and parents or guardians by questionnaires. RESULTS: Desire for treatment was higher among children in the publicly funded clinics and among black children than whites or Asian Americans. Children in publicly funded clinics rated themselves as having worse occlusions as determined by anterior crowding, overbite, overjet, diastema, and open bite. Children in the Bronx clinic accepted a wider range of occlusion as attractive. Stage of treatment affected judgments of attractiveness. Vicarious experience with orthodontics through parents or siblings made children more tolerant of dentofacial disharmony, with more favorable ratings of malocclusion in this group than among children who had no family experience with orthodontics. Hispanic and mixed-ethnicity children rated themselves more negatively on all dimensions. CONCLUSIONS: These results suggest that both socioeconomic status and ethnicity play roles in children's desire for treatment, self-assessed need, and judgments of esthetics. A clinician's sensitivity to such differences can improve patient cooperation with treatment.

Child↗
PubMed2006

Class III surgical-orthodontic treatment: a cephalometric study.

INTRODUCTION: In this retrospective study, we investigated treatment outcomes in Class III surgical-orthodontic patients. METHODS: Records of 151 consecutively completed Class III surgical-orthodontic patients (overjet, 0 mm or less) were obtained from 87 consultant orthodontists in the United Kingdom. Pretreatment and posttreatment cephalometric radiographs were analyzed. RESULTS: Bimaxillary surgical patients (75%) had more negative initial ANB-angle values and smaller initial SNA-angle values than those treated with single-jaw mandibular surgery. Mandibular surgery patients (15%) had greater pretreatment mandibular prominence (SNB angle) than maxillary patients. Maxilla-only patients (10%) had lower negative initial overjet values than bimaxillary patients. An overjet within the ideal range of 1 to 4 mm was achieved in 83% of the patients. Logistic regression identified no predictors of ideal overjet outcome. SNB angle was corrected to within the ideal range of 75 degrees to 81 degrees in 44% of the patients. This was less likely in those treated with maxillary surgery only and larger initial SNB-angle values. An ideal posttreatment ANB angle (1 degrees to 5 degrees) was achieved in 40% of the patients and was more likely in those with bimaxillary surgery, lower negative pretreatment ANB angles, and presurgical orthodontic extractions in the maxillary arch. Ideal posttreatment unadjusted Holdaway angles (7 degrees to 14 degrees) were achieved in 59% of the patients and were more likely when single-jaw mandibular surgery was used. Incisor decompensation was incomplete in 46% of the patients and was associated with mandibular arch extractions. CONCLUSIONS: Surgical-orthodontic treatment had a high success rate in normalizing the overjet and soft-tissue profile to within ideal ranges in Class III patients. Bimaxillary surgery was the most frequently used procedure and was associated with an increased likelihood of an ideal correction of the anteroposterior skeletal discrepancy.

Adolescent↗
PubMed2006

Body dysmorphic disorder in adult orthodontic patients.

INTRODUCTION: Body image plays an important role for patients seeking orthodontic treatment. It affects how patients feel about their physical appearance and, in extreme cases, can lead to subjective fears of ugliness. When there is a physical defect that, although within normal limits, seems far more noticeable to the patient, this may be diagnosed as body dysmorphic disorder (BDD). This interview-based study was designed to assess BDD in adults attending the Orthodontic Department at the Eastman Dental Hospital in London for their initial consultations for orthodontic treatment and also in the general public. METHODS: A total of 70 members of the general public and 40 patients, all over 18 years of age, were assessed. The BDD modification of the Yale-Brown obsessive compulsive scale was used for diagnosis of BDD. RESULTS: BDD was diagnosed in 2 members of the general public (2.86%) and 3 patients (7.5%). CONCLUSIONS: It is important to have an understanding of body image and to be able to identify orthodontic patients who have BDD. These patients are rarely satisfied with the results of treatment, and it is therefore important to recognize them to avoid unnecessary treatment and to refer them for appropriate management.

Adult↗
PubMed2006

Determining the limits of orthodontic treatment of overbite, overjet, and transverse discrepancy: a pilot study.

INTRODUCTION: Because of the severity of some malocclusions, it is not always possible to treat them without a combination of orthodontics and orthognathic surgery. However, many insurance carriers have difficulty in deciding whether such treatment should be covered. The purpose of this study was to develop a simple method that can be used by insurance carriers to determine when a malocclusion is not correctable by orthodontics alone. METHODS: Twenty-eight orthodontists independently evaluated 30 sets of pretreatment dental models (10 with overjet from -6 to 12 mm, 10 with overbite from 60% to 100%, and 10 with transverse discrepancies from single tooth to total arch crossbite) to determine whether the conditions were orthodontically treatable. They were instructed to assume that growth was complete and that the treatment would not seriously compromise facial esthetics. RESULTS: It was the opinion of the orthodontists that a positive overjet greater than 8 mm, a negative overjet of -4 mm or greater, and a transverse discrepancy greater than 3 mm were not orthodontically treatable. However, most orthodontists believed that they could treat all overbite patients without surgery. CONCLUSIONS: These data can serve as a simple guideline for helping insurance carriers determine the need for orthognathic surgery.

Feasibility Studies↗
PubMed2006

Search and selection methodology of systematic reviews in orthodontics (2000-2004).

INTRODUCTION: More systematic reviews related to orthodontic topics are published each year, although little has been done to evaluate their search and selection methodologies. METHODS: Systematic reviews related to orthodontics published between January 1, 2000, and December 31, 2004, were searched for their use of multiple electronic databases and secondary searches. The search and selection methods of identified systematic reviews were evaluated against the Cochrane Handbook's guidelines. RESULTS: Sixteen orthodontic systematic reviews were identified in this period. The percentage of reviews documenting and using each criterion of article searching has changed over the last 5 years, with no recognizable directional trend. On average, most systematic reviews documented their electronic search terms (88%) and inclusion-exclusion criteria (100%), and used secondary searching (75%). Many still failed to search more than MEDLINE (56%), failed to document the database names and search dates (37%), failed to document the search strategy (62%), did not use several reviewers for selecting studies (75%), and did not include all languages (81%). CONCLUSIONS: The methodology of systematic reviews in orthodontics is still limited, with key methodological components frequently absent or not appropriately described.

Databases, Bibliographic↗
PubMed2005

An investigation into the use of an anaerobic adhesive with two commercially available orthodontic brackets.

OBJECTIVES: The two objectives of this experiment were to determine the surface temperature of enamel following acid etching, rinsing and drying, and to see whether two commercially available orthodontic brackets could be bonded to enamel using an anaerobic adhesive. METHODS: Enamel surface temperature was determined in vivo using a surface temperature probe on a total of 60 patients. Stainless steel orthodontic brackets were bonded to human enamel using an anaerobic adhesive and a control orthodontic adhesive. The enamel was etched prior to bonding either with a solution of 37% o-phosphoric acid or, in the case of the anaerobic adhesive specimens, with a solution of 37% o-phosphoric acid containing copper (II) chloride. After bench curing the specimens were shear bond tested to failure and the load at debond recorded in each case. RESULTS: The bond test results were analyzed using median force to debond (N) and 95% confidence intervals, Kaplan-Meier survival probabilities and log-rank tests. CONCLUSIONS: After etching rinsing and drying the enamel surface temperature ranged from 21.54 to 24.19 degrees C, which is within the range suitable for anaerobic adhesive use. Bond testing to failure demonstrated that bracket base design affected the measured force to debond with both the anaerobic adhesive under test and the control adhesive. In addition, the anaerobic adhesive was affected by the material composition of the bracket base and curing time. After 1h of curing and using the Miniature Twin bracket, the measured force to debond exceeded the 10 min force to debond results of the control adhesive. SIGNIFICANCE: It is possible to bond commercially available orthodontic brackets to teeth using an anaerobic adhesive.

Acid Etching, Dental↗
PubMed2006

Variation in surface topography of different NiTi orthodontic archwires in various commercial fluoride-containing environments.

OBJECTIVES: The surface topography can affect the friction behavior between an orthodontic wire and brackets during clinical applications. The purpose of this study was to investigate the influence of a fluoride-containing environment on the surface topography variations of different nickel-titanium (NiTi) orthodontic archwires. METHODS: Four different NiTi commercial orthodontic archwires were immersed in fluoride mouthwashes and in artificial saliva with the addition of commercial fluoride toothpastes or prophylactic gels for a 28-day period. Atomic force microscopy (AFM) was used to measure the three-dimensional surface topography of NiTi archwires before and after the immersion tests. Two-way analysis of variance (ANOVA) was used to analyze the surface roughness variance (including DeltaR(a), DeltaR(ms), and DeltaR(z)) with the archwire manufacturer and immersion test environment as the factors. RESULTS: Both the archwire manufacturer and immersion environment had a significant influence on DeltaR(a), DeltaR(ms), and DeltaR(z) (manufacturer: P<0.05; environment: P<0.0001). Regardless of the archwire manufacturer, no statistically significant difference in DeltaR(a) (<70 nm), DeltaR(ms) (<90 nm), and DeltaR(z) (<450 nm) was observed on the tested NiTi archwires in lower fluoride-containing (<2500 ppm) environments, including the various fluoride mouthwashes and the artificial saliva added with fluoride toothpastes. In artificial saliva added with high fluoride prophylactic gel (around 17,000 ppm), a significant increase in DeltaR(a) (around 120-250 nm), DeltaR(ms) (around 140-320 nm), and DeltaR(z) (around 770-1410 nm), i.e. increasing the surface roughness, was observed on the tested NiTi archwires. SIGNIFICANCE: The variation in the surface topography of the NiTi orthodontic archwires in the commercial fluoride-containing environments should be taken into consideration when the friction between the archwire and bracket is a clinical concern.

Acidulated Phosphate Fluoride↗
PubMed1983

Orthopedic effects with "conventional" fixed orthodontic appliances: a preliminary report.

This retrospective study involved sixty previously treated patients between the ages of 9 and 14 years, all of whom initially had Class II dental malocclusions. The primary purpose of the investigation was to determine whether orthodontic treatment with a specific round-wire edgewise technique (no extraoral forces) was simply producing dentoalveolar manipulations or was actually affecting measurable skeletal or orthopedic alterations in the craniofacial system. The mean linear changes before and after orthodontic treatment in the maxilla (Ar-ANS), mandible (Ar-PGN), and lower facial height (ANS-MN) were statistically compared with an untreated control group (the Burlington Growth Study). The study sample was analyzed selectively according to sex and also according to the angulation of the mandibular base to the anterior cranial base (the SNMP angle). Apparently, from the observations in this study, the particular edgewise technique employed for the orthodontic treatment of the sixty sample patients did statistically affect more than merely dentoalveolar alterations. The normal forward growth of the maxilla appeared to be hindered, the lower facial height was significantly increased (usually without an appreciable increase in the SNMP angle), and the mean increased growth of the mandible was also statistically significant. Admittedly not its primary purpose, this preliminary report appeared to at least indirectly compare, if not the actual treatment modalities, at least the treatment results between a specific fixed orthodontic appliance and certain removable "functional" appliances.

Adolescent↗
PubMed2002

Cytotoxicity of orthodontic bands, brackets and archwires in vitro.

OBJECTIVES: In orthodontic therapy, different materials are used and subjected to a damp oral environment, which can modify their properties. In order to evaluate the biocompatibility of metallic and non-metallic orthodontic appliances their in vitro cytotoxicity has been measured. METHODS: Twenty-eight new and nine clinically used materials, including brackets, molar bands and archwires were used. The metallic materials were made of stainless steel, gold-plated steel, pure titanium, nickel-titanium, titanium-molybdenum and silver-based soldering alloy. The non-metallic materials were in polycarbonates and ceramics. After a release period of the material in the culture medium (0.1 mg/ml) for 3 and 14 days, the viability of fibroblasts L929 cultivated with this medium was compared to negative control with MTT assay. RESULTS: The results showed the non-cytotoxicity of the materials. The metallic and non-metallic materials were similar in terms of cytotoxicity. The cytotoxicity of clinically used samples was equivalent to that of the same non-used samples, except a cytotoxic sample, at 14 days, corresponding to a soldered and clinically used molar band. The 3 day results were different from the 14 day results in six cases out of 37. SIGNIFICANCE: In spite of the presence of one cytotoxic sample, the orthodontic materials can be considered as non cytotoxic. However, the practitioner should pay attention to the composition and the polish of soldering silver-based alloys containing copper and zinc in order to limit cytotoxic ion release. The cytotoxicity of the used sample related to ion release might be related to some clinical sub-acute effects related with orthodontic materials, thus a long term release period may be suitable to evaluate in vitro the sub-acute clinical effects of alloys.

Analysis of Variance↗