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At least 955 records · Page 53Linked to original sources
PubMed2000

A comparison of growth impairment and orthodontic results in adult patients with clefts of palate and unilateral clefts of lip, palate and alveolus.

OBJECTIVE: To evaluate and compare the long-term aesthetic and functional results of surgical and orthodontic treatment in patients with cleft palate and unilateral cleft lip, palate, and alveolus. DESIGN: 30 patients with unilateral cleft lip, palate, and alveolus and 30 patients with isolated cleft palate, mean age of 18.9 years, were evaluated by cephalometric and model analysis a mean of 1.5 years after orthodontic treatment. In each group the surgical treatment has been similar. RESULTS: Model analysis: The sum of every mesiodistal tooth diameter in the maxilla and in the mandible was recorded according to the Bolton analysis. Twenty patients with unilateral cleft lip, palate and alveolus had relatively large upper dental arches and nine had relatively large lower dental arches. Twenty-two patients with cleft palates had large upper dental arches and seven had large mandibular arches. Eleven patients with unilateral cleft lip, palate, and alveolus and 18 patients with cleft palate had a negative space supply (the sum of the mesiodistal tooth diameters compared with the sagittal length of the alveolar ridge) in the region of the lateral teeth. All patients had persistent transverse space deficits that were increased on the side of the cleft in patients with cleft lip, palate, and alveolus. These unilateral transversal space deficits were recorded in 22 patients with unilateral cleft lip, palate, and alveolus and in 8 patients with isolated cleft palate. Sagittal measurements were reduced in 26 patients with unilateral cleft lip, palate, and alveolus and in 23 patients with cleft palate alone. The alveolar midline of the maxilla and the mandible were displaced in 25 patients with unilateral cleft lip, palate, and alveolus and in 19 patients with isolated cleft palate. Lateral cephalometric analysis: The lateral cephalograms taken at the same time as the models showed a mean SNA of 76.8 degrees and a NL-NSL angle of 8.7 degrees, indications of a tendency towards maxillary retrognathia in patients with unilateral cleft lip, palate, and alveolus. Patients with cleft palate had a mean SNA of 79.6 degrees and NL-NSL angle of 8.1 degrees. The anterior facial vertical index was within normal limits in patients with cleft lip, palate, and alveolus (44% vs 56%). An anterior facial height index of 42% compared with 58% in patients with isolated cleft palate indicated a slight reduction in midface height with an increase in the lower face as a consequence. CONCLUSION: Orthodontic and surgical treatment can result in satisfactory results on model analysis. However, there is specific growth impairment of the maxilla 1.5 years after termination of orthodontic treatment and this influences the final cephalometric analysis, particularly in patients with cleft lip, palate, and alveolus.

Adolescent↗
PubMed2002

The influence of orthodontics on selection and breakage underlying food comminution in pre-orthognathic surgery patients.

Comminution of food is the composite result of selection and breakage. Selection is characterized by the chance that a food particle will at least be damaged by the teeth during a chew. For any particle size, this chance equals the ratio between the weight of damaged and broken particles and that of all initial particles. The breakage process refers to fracturing of selected particles. Since orthodontic treatment applied to patients before orthognathic surgery has an effect on the position and orientation of teeth, it may alter chewing efficiency by influencing selection and/or breakage. The effect of such orthodontic treatment on chewing efficiency was examined using eight cubes of 8.0 mm of a silicone-rubber (Optosil) as a test food for determining the number of chews required to halve the initial particle size (N(1/2)) in 12 patients. Three particle sizes (2.4, 4.8 and 8.0 mm) were used for determining selection and breakage in one-chew experiments. Orthodontic treatment had no effect on the chewing efficiency and the selection chances of all particle sizes whereas the degree of breakage was significantly (P<0.05) increased only for a particle size of 8.0 mm. These findings suggest that presurgical orthodontics has only a minor effect on food comminution.

Adult↗
PubMed2005

[Orthodontic brackets in high field MR imaging: experimental evaluation of magnetic field interactions at 3.0 Tesla].

PURPOSE: To evaluate static magnetic field interactions for 32 commonly used orthodontic brackets in a 3.0 T magnetic resonance imaging (MRI) system. MATERIALS AND METHODS: 32 orthodontic brackets consisting of a steel alloy (n = 27), a cobalt-chromium alloy (n = 2), ceramic (n = 1), ceramic with a steel slot (n = 1), and titanium (n = 1) from 13 different manufacturers were tested for magnetic field interactions in a static magnetic field at 3.0 T (Gyroscan Intera 3.0 T, Philips Medical Systems, Best, Netherlands). The magnetic deflection force F (z) [mN] was evaluated by determining the deflection angle beta [ degrees ] using the established deflection angle test according to the ASTM guidelines. The magnetic-field-induced rotational force F (rot) or torque was qualitatively determined using a 5-point grading scale (0: no torque; + 4: very strong torque). RESULTS: In 18 of the 32 brackets, the deflection angle beta was found to be > 45 degrees and the translational force exceeded the gravitational force F (G) on the particular bracket (F (z): 1.2 - 45.7 mN). The translational force F (z) was found to be up to 68.5 times greater than the gravitational force F (G) (F (z)/F (G): 1.4 - 68.5). The rotational force F (rot) was correspondingly high (+ 3/+ 4) for those brackets. For the remaining 14 objects, the deflection angles were < 45 degrees and the torque measurements ranged from 0 to + 2. The static magnetic field did not affect the titanium bracket and the ceramic bracket. No measurable translational and rotational forces were found. CONCLUSION: Of the 32 brackets investigated for magnetic field interactions at 3.0 T, 18 (56.25 %) were unsafe in the MR environment according to the ASTM guidelines. However, the forces measured were minimal compared to the forces generally necessary for dislodging these bonded orthodontic brackets from tooth surfaces. The implications of these results for orthodontic patients undergoing MR examinations at 3 Tesla are discussed.

Humans↗
PubMed2001

Open gingival embrasures after orthodontic treatment in adults: prevalence and etiology.

The purposes of this study were to determine the prevalence of posttreatment open gingival embrasures in adult orthodontic patients and to examine the association of pretreatment maxillary incisor malalignment, posttreatment alveolar bone height, interproximal contact position, root angulation, crown shape, and embrasure area with open gingival embrasures. Posttreatment intraoral photographs of 337 adult orthodontic patients were evaluated to determine the prevalence of open gingival embrasures. A subsample of 119 patients was identified for measurement and divided into 2 groups: normal gingival embrasures and open gingival embrasures. Digital images of the pretreatment maxillary models and posttreatment maxillary central incisor periapical radiographs were made to measure the pretreatment and posttreatment variables. The prevalence of posttreatment open gingival embrasures in adult orthodontic patients was 38%. Pretreatment maxillary central incisor rotation and overlap were not statistically associated with posttreatment open gingival embrasures. A posttreatment alveolar bone-interproximal contact distance greater than 5.5 mm was associated with open gingival embrasures. Short and more incisally positioned posttreatment interproximal contacts were associated with open gingival embrasures. Open gingival embrasures were found to have more divergent root angulations and more divergent or triangular-shaped crown forms than normal gingival embrasures. Embrasure areas larger than 5.09 mm(2) were also correlated with open gingival embrasures. Increased alveolar bone-interproximal contact distance and increased root angulation demonstrated the greatest increase in the odds of an association with an open gingival embrasure. This investigation indicates that open gingival embrasures are common in adults who have undergone orthodontic treatment and that posttreatment variables are significant factors in open gingival embrasures.

Adult↗
PubMed2001

Preparing to practice and manage: A program for educating orthodontic residents in practice management.

The purpose of this article is to describe how the integration of practice management principles into orthodontic graduate programs can help young practitioners avoid many of the mistakes commonly made in developing an orthodontic practice and to provide guidelines and resources for starting off in the right direction. This article also describes how practice management education was integrated as one of the 4 principal components of contemporary orthodontic education at a California university. Specific goals, concepts, and components of a comprehensive practice management program are outlined. A structured practice management curriculum can provide opportunities for residents and alumni to learn some of the latest developments and techniques in orthodontic practice management.

Curriculum↗
PubMed2002

Orthodontic treatment outcome in a First Nations population in Alberta, Canada: a comparative study.

The primary objective of this study was to determine whether there was a significant difference in the degree of improvement after orthodontic treatment between a sample of First Nations orthodontic patients and a control sample of non-First Nations orthodontic patients. The secondary objective was to determine whether there was a difference in the severity of malocclusions being treated in a sample of the First Nations patients compared with a control sample of the non-First Nations patients. Several factors that might affect treatment outcome, such as missed appointments, treatment duration, oral hygiene, extractions, dental classification, and geographic location, were also studied. A sample of 60 First Nations patients and a control group of 60 non-First Nations patients between the 11 and 18 years of age who had been treated with full fixed orthodontic appliances were evaluated. The weighted peer assessment rating (PAR) index was applied to pretreatment and posttreatment study models to address the study's main objectives. The results showed that the First Nations group had greater PAR scores pretreatment than did the controls, and their weighted PAR scores improved more with treatment. Posttreatment PAR scores were similar between the 2 groups. In addition to First Nations status, only extractions and geographic location affected PAR improvement scores.

Adolescent↗
PubMed2002

Use of an onplant as orthodontic anchorage.

Considerable limitations in the clinical application of orthodontic treatment can result from the lack of teeth suitable for anchorage. If prosthetic rehabilitation is necessary, endosseous implants can be first used as orthodontic anchorage and then loaded by a prosthetic superstructure. However, in a plan of exclusive orthodontic treatment, alveolar bone is not always available, and an orthodontic osseointegrated anchorage system might be necessary. We report the use of an onplant for palatal anchorage to extrude the unerupted horizontal maxillary first molars in a 12-year-old white girl with tooth aplasia and secondary cleft palate. After a healing period of 5 months, the onplant remained stable under indirect elastic tension of approximately 160 g applied for 17 weeks, and the maxillary first molars were successfully extruded.

Alveolar Ridge Augmentation↗
PubMed2003

Long-term follow-up of Class II adults treated with orthodontic camouflage: a comparison with orthognathic surgery outcomes.

Thirty-one adults who had been treated with orthodontics alone for Class II malocclusions were recalled at least 5 years posttreatment to evaluate cephalometric and occlusal stability and also their satisfaction with treatment outcomes. The data were compared with similar data for long-term outcomes in patients with more severe Class II problems who had surgical correction with mandibular advancement, maxillary impaction, or a combination of those. In the camouflage patients, small mean changes in skeletal landmark positions occurred in the long term, but the changes were generally much smaller than in the surgery patients. The percentages of patients with a long-term increase in overbite were almost identical in the orthodontic and surgery groups, but the surgery patients were nearly twice as likely to have a long-term increase in overjet. The patients' perceptions of outcomes were highly positive in both the orthodontic and the surgical groups. The orthodontics-only (camouflage) patients reported fewer functional or temporomandibular joint problems than did the surgery patients and had similar reports of overall satisfaction with treatment, but patients who had their mandibles advanced were significantly more positive about their dentofacial images.

Adolescent↗
PubMed1997

Increase of the vertical occlusal dimension by means of a removable orthodontic appliance and its effect on craniocervical relationships and position of the cervical spine in children.

The aim of this study was to determine the effect of the increase in the occlusal vertical dimension by means of an orthodontic appliance on craniocervical relationships and position of the cervical spine. Thirty children presenting malocclusion were divided into two groups of 15 (a study and a control group). Those in the study group wore an orthodontic appliance to correct cross-bite. The children in the control group had no treatment during the experimental period. Two lateral craniocervical radiographs were taken for each child. The first one was taken in the intercuspal position in both groups. The second radiograph was taken of the study group after four months of wearing the appliance and also of the control group after four months. Cephalometric analysis in the study group showed a significant forward cervical spine position. There were no significant changes in the control group. The changes found in the study group suggest that when there are signs and symptoms of cervical dysfunction in children undergoing long-term orthodontic treatment, it is necessary to make an evaluation of the cervical column position after the insertion of any orthodontic appliance which increases the occlusal vertical dimension.

Case-Control Studies↗
PubMed1999

Removal of orthodontic bonding resin residues by CO2 laser radiation: surface effects.

OBJECTIVE: The purpose of this in vitro study was to evaluate the potential use of pulsed CO2 laser radiation to remove selectivity residues of orthodontic bonding resin that remain after debonding of fixed orthodontic appliances. SUMMARY BACKGROUND DATA: Current techniques used for removal of orthodontic bonding resin after removal of fixed appliances include rotary instruments, debonding pliers, and ultrasonic scalers. These techniques, however, are time-consuming and inefficient, and may damage tooth enamel. METHODS: A standardized cylinder of orthodontic bonding resin was bonded to the buccal surfaces of 100 extracted premolar teeth, which were then divided into 10 groups of 10 specimens each. In 9 groups, the resin was ablated using 1 of 9 different laser parameters, while in the remaining control group, the resin was removed with a slow speed tungsten carbide bur. Specimens were evaluated by light microscopy and scanning electron microscopy (SEM) to assess the amount of resin remaining and the extent of the damage to the underlying enamel. RESULTS: The 2 W/100 ms combination was optimal, with a high efficiency of resin removal and the least enamel damage. Higher laser powers increased the extent of enamel damage without enhancing resin removal. CONCLUSIONS: This laser technique appears promising, however, further studies of the extent of thermal changes at the level of the dental pulp are necessary to establish more fully the risk-benefit ratio.

Analysis of Variance↗
PubMed1990

Nickel allergy and orthodontic treatment.

Nickel is the most common contact allergen affecting females in Europe and the USA. Nickel-containing metal alloys are extensively used for dental prostheses and orthodontic appliances. The aim of this study was to elucidate whether nickel sensitive persons are at greater risk of developing discomfort in the oral cavity during orthodontic treatment. Data from 1085 consecutive girls in active orthodontic treatment or in retention were collected by means of a questionnaire. No nickel allergic reaction on the oral mucosa was found. The majority of the girls with unspecific mucosal reactions and skin lesions were atopics with a chronic dermatitis. The findings do not indicate that nickel sensitive persons are at greater risk of developing discomfort in the oral cavity when wearing an intraoral orthodontic appliance.

Adolescent↗
PubMed1990

Diagnostic value of clinical examination for the identification of children in need of orthodontic treatment compared with clinical examination and screening pantomography.

Ninety children in the 5th school grade (means age = 11.9 years) participated in this investigation. As part of the orthodontic screening examination, pantomograms of all children had been performed as a routine procedure. Prior to assessment of the pantomograms each child was assigned to one of the following treatment categories based on clinical examination: -T (no indication for orthodontic treatment), O (observation of dentition development) and +T (indication for orthodontic treatment). Children, in whom clinical symptoms gave rise to a radiographic examination, were selected and their pantomograms assessed. Finally, the pantomograms of all children were interpreted, and the clinically established treatment categories re-evaluated on basis of the findings on the pantomograms. Fifteen children were selected for pantomography, but only one changed treatment category (from O to +T) due to observation of developmentally missing premolars. Three of the children not selected for pantomography changed categories from -T; two to O and one to +T. Clinical examination with selective pantomography was thus able to correctly identify 97 per cent of children in need of immediate orthodontic treatment, while it was able to correctly exclude 94 per cent of the healthy children. On the basis of these results, routine screening pantomography may be omitted.

Anodontia↗
PubMed1991

TMJ function with and without orthodontic treatment.

In order to evaluate the functional status of the stomatognathic system of former orthodontic patients, a review of current literature is given. In addition, a sample of orthodontically-treated subjects and a control group was investigated by means of clinical functional analysis. The figures found in the literature and the results of this study failed to reveal orthodontic treatment as a frequent cause of stomatognathic dysfunction symptoms. Instead, we found the functional status and occlusal parameters of our former orthodontic patients to be more harmonious than in the control group.

Adult↗
PubMed1993

Radiological variations in mandibular condyles of Finnish students, one group orthodontically treated and the other not.

Panoramatomograms of 968 students (355 males and 613 females) aged between 19 and 25 years were evaluated with special emphasis on the mandibular condyles. Two-hundred-and-thirty-five students (24.3 per cent) had been treated orthodontically. Radiographic variations in the condyles were significantly more common in the orthodontically treated group as a whole and in males (n = 71, P < 0.001), but not in females (n = 164). No age correlation in the frequency of condylar variations was found in either group. In terms of individual severe variation, flattening of the articular surface (P < 0.001) and subcortical sclerosis (P < 0.01) were more common in the orthodontically treated students. In the untreated subjects (284 males and 449 females), females had more variations (9.3 per cent) in their condyles than males (3.7 per cent P < 0.001). In the orthodontically treated students the percentages with condylar variations were 21.1 per cent in males and 16.5 per cent in females (N.S.).

Adult↗
PubMed1995

Prevalence and severity of apical root resorption of maxillary anterior teeth in adult orthodontic patients.

The purpose of this study was to evaluate prevalence and severity of apical root resorption of maxillary anterior teeth in a large sample of adult orthodontic patients, to analyse any difference between subgroups of patients with and without a history of earlier orthodontic treatment, and to test the hypothesis that endodontically treated teeth are less likely to experience apical root resorption. Differences in tooth length measurements of standardized periapical radiographs made before and after treatment of 343 adults, representing groups of consecutively treated patients from four orthodontic practices, were calculated. Sample means of averaged root resorption of all six anterior teeth and of the most severely resorbed tooth per patient were 0.94 mm (SD 0.88) and 2.39 mm (SD 1.43), respectively. Forty per cent of the adults had one or more teeth with 2.5 mm resorption or greater. The subsample of 31 patients with a history of earlier orthodontic treatment had less root resorption than the remaining patients (P < 0.001). Evaluation of the 39 contralateral pairs of teeth with and without endodontic treatment in 36 of the patients revealed less resorption of the endodontically treated teeth (P < 0.05).

Adult↗
PubMed1995

Expression of neuropeptides (CGRP, substance P) during and after orthodontic tooth movement in the rat.

The present study was designed to investigate the changes in patterns of calcitonin gene-related peptide (CGRP) and substance P (SP) innervation during buccally-directed orthodontic tooth movement (OTM) of the first maxillary molar in the rat. In addition, the CGRP- and SP-innervation was examined 14 and 28 days after the orthodontic force was discontinued. Comparisons were made with the innervation found in control animals. Orthodontic appliances produced a buccally directed force in the range of 20-50 g on the upper right first molar for either 24 hours or 3 days. When the orthodontic appliances were removed one group of animals were killed immediately, whereas the other groups were killed after a healing period of 14 days or 28 days. After fixation the upper jaws were decalcified, frozen, and sectioned in the frontal plane at the level of the first and second molars. The sections were processed for CGRP, SP, and routine morphology. An increase was found in the number of nerve fibres showing CGRP-like immunoreactivity (LI) in the pulp, periodontal ligament (PDL) and marginal gingivae with the fibres showing a higher intensity of immunolabelling after 24 hours or 3 days of OTM. The contralateral first upper molar showed an increase in the expression of CGRP. Fourteen days after removal of the appliances, there was still a marked CGRP-innervation of the PDL in test teeth as well as in contralateral teeth. After 28 days, a decrease in CGRP-innervation was observed, but this innervation was still more pronounced than that found in the controls. The pattern of SP-innervation changed similarly to that of the CGRP-innervation, however, the nerve fibres showing SP-LI were considerably fewer than those showing CGRP-LI at all stages and in all areas. This study suggests that CGRP- and SP-changes not only occur in the tooth exposed to buccally directed OTM, but also in the contralateral tooth and that the changes are evident for a considerable time after terminating OTM.

Animals↗
PubMed1996

Enamel fluoride levels after orthodontic band cementation with glass ionomer cement.

The aim of this investigation was to examine the fluoride uptake by enamel after application of glass ionomer cement for orthodontic band cementation compared with zinc phosphate cement. The study was conducted on 21 children whose mean age was 14 years. All the children were reared in the Middle Anatolian cities where the water fluoride concentration was below the level of 0.50 ppm. The subjects were randomly divided into three groups. The first experimental group, had seven subjects whose teeth were topically fluoridated with 2 per cent NaF solution, before orthodontic band cementation with zinc phosphate cement. The second experimental group also had seven subjects whose orthodontic bands were cemented with glass ionomer cement. The third group, consisted of seven control subjects and no dental procedures were performed in this group. All the participants were followed for 3 months and at the end of this period maxillary first premolars, which were in the ninth developmental stage according to Nolla (1960), were extracted for orthodontic purposes. The enamel fluoride concentrations were determined on the left maxillary first premolars at three successive etch depths by means of a fluor ion electrode, whereas the calcium concentrations were determined with an atomic absorption spectrophotometer. The results of this investigation showed that in both cementation groups enamel fluoride concentrations at three successive etch depths were highly increased compared with the control group. However, the difference between the cementation groups was not statistically significant.

Adolescent↗
PubMed1998

Surface roughness of orthodontic wires via atomic force microscopy, laser specular reflectance, and profilometry.

The surface roughness of orthodontic archwires is an essential factor that determines the effectiveness of arch-guided tooth movement. Using the non-destructive techniques of atomic force microscopy (AFM) and of laser specular reflectance, the surface roughness of 11 nickel-titanium orthodontic wires, a stainless steel and a beta-titanium wire was measured. The results were compared with those obtained using surface profilometry. The smoothest wire, stainless steel, had an optical roughness of 0.10 micron, compared with 0.09 micron from AFM and 0.06 from profilometry. The surface roughness for the beta-titanium wire measured by all three methods was approximately 0.21 micron, while that of the NiTi wires ranged from 0.10 to 1.30 microns. As the surface roughness not only affects the effectiveness of sliding mechanics, but also the corrosion behaviour and the aesthetics of orthodontic components, the manufacturers of orthodontic wires should make an effort to improve the surface quality of their products.

Corrosion↗