Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ORTHODONTICS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,459 records · Page 81Linked to original sources
PubMed2002

A comparison of shear bond strengths of orthodontic brackets using various light sources, light guides, and cure times.

The objective of this study was to evaluate the effects of different cure times, light sources, and light guides on shear bond strength of orthodontic brackets bonded with Transbond XT (3M Unitek, Monrovia, Calif) to bovine enamel. Specifically, the Power Slot (Reliance Orthodontic Products, Itasca, Ill) light guide was placed on 4 visible light sources to compare shear bond strengths and recommended cure times with the light guides provided with each light source. We randomly divided 240 bovine mandibular incisors into 16 groups; each group consisted of 15 teeth mounted in an acrylic block. Each group of teeth was polymerized with a specific light and light guide combination. Eight groups were sheared after 5 minutes and the remaining 8 groups after 24 hours. After bonding, all brackets were subjected to a shear force with a testing machine. Overall, there was a significant increase in bond strengths of the 24-hour groups compared with the 5-minute shearing groups. However, there were no statistical differences (P =.05) within the 24-hour test groups or the 5-minute test groups. The results of this study indicate that, compared with standard light guides, the Power Slot and the Turbo Tip (Ormco Sybron Dental Specialties, Orange, Calif) light guides can significantly reduce the curing times (10 seconds per bracket; 5 seconds each from mesial and distal) without affecting their shear bond strengths. Therefore, the Power Slot and the Turbo Tip light guides with their collimation of visible light to increase its intensity can be recommended as advantageous alternatives for curing composite resins for orthodontic bonding procedures.

Analysis of Variance↗
PubMed2002

A comparison of in vitro enamel demineralization potential of 3 orthodontic cements.

The objective of this in vitro study was to compare resistance to enamel demineralization after banding with 3 orthodontic cements. The 3 orthodontic cement groups and the nonbanded control group were evaluated for cariopreventive potential. One hundred twenty extracted human molars were selected for banding, embedded in resin blocks, and randomly assigned to the following 4 groups: zinc phosphate cement, zinc polycarboxylate cement, resin-modified glass ionomer (RMGI), and nonbanded control. Orthodontic bands were placed and cemented; specimens were stored in artificial saliva at 37 degrees C for 30 days, thermocycled for 24 hours, and then debanded with a customized band-removal device attached to a universal testing machine. The cement was hand removed, and 2 coats of nail varnish were applied to the teeth, leaving a 2 x 2-mm window exposed on the buccal surface of the mesiobuccal cusp. The teeth were stored in lactic acid-gelatin solution for 4 weeks at 37 degrees C to develop simulated white spot decalcification in the window. The teeth were subjected to dye (10% methylene blue) for 24 hours and then sectioned through the window. The depth of dye penetration was determined and used as a measure of the cariopreventive effect of the banding cement. Data were analyzed with a 1-way ANOVA and a Tukey test for the multiple comparisons. Dye penetration occurred as follows: the zinc phosphate and control groups were about the same; there was less dye penetration with the zinc polycarboxylate, and the least with the resin-modified glass ionomer. The 2 fluoride-releasing cements (zinc polycarboxylate and RMGI) demonstrated less demineralization than the zinc phosphate in vitro and might provide greater protection from demineralization around a band periphery in clinical settings.

Analysis of Variance↗
PubMed2002

The effect of repeated bonding on the shear bond strength of different orthodontic adhesives.

One problem clinicians face during treatment is bracket failure. In a busy orthodontic practice, a significant number of teeth will need to be rebonded. The purpose of this study was to evaluate the effect of repeated bonding with 2 different adhesives, a composite and a cyanoacrylate, on the shear bond strength of orthodontic brackets. Thirty-one freshly extracted human molars were collected. Brackets were bonded with 1 of the orthodontic adhesives according to the manufacturer's instructions. In group I, the teeth were etched with 37% phosphoric acid, a sealant was applied, and the brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif) and light cured for 20 seconds. In group II, the teeth were etched with 35% phosphoric acid, and the brackets were bonded with SmartBond (Gestenco International, Göthenburg, Sweden). In each group, the teeth were bonded and debonded 3 times with the same adhesive. At each sequence, the brackets were removed within 30 minutes after bonding to simulate the clinical condition at which a newly bonded bracket is tied to the archwire. Student t tests and the analysis of variance repeated measure were used to compare the shear bond strength between adhesives and within each adhesive at different debonding sequences. The results indicated that, at the first debonding sequence, the 2 adhesives did not have significantly different shear bond strengths. Between debonding sequence 1 and 2, there was a significant (P <or=.05) decrease in the shear bond strength of both adhesives. SmartBond decreased from x = 5.7 +/- 3.8 MPa to x = 2.2 +/- 2.6 MPa, and Transbond decreased from x = 6.1 +/- 3.4 to x = 4.1 +/- 2.3 MPa. When the 2 adhesives were compared at the second debonding sequence, the shear bond strength of Transbond was significantly greater than that of SmartBond (P =.046). Between debonding sequences 2 and 3, there were no significant differences either between the adhesives or in the change within each adhesive. The highest values for shear bond strength were obtained after the initial bonding. Rebonded teeth had significantly lower shear bond strength. The composite adhesive had a higher shear bond strength than the cyanoacrylate adhesive at the second bonding/debonding sequence but not at the third. The changes in bond strength after repeated bonding may be related to changes in the morphologic characteristics of the tooth surface caused by adhesive remnants.

Analysis of Variance↗
PubMed2002

Treatment decision in adult patients with Class III malocclusion: orthodontic therapy or orthognathic surgery?

Class III malocclusion is one of the most difficult anomalies to understand. Because not all Class III patients are candidates for surgical correction, patient assessment and selection remain main issues in diagnosis and treatment planning. The purpose of this study was to separate Class III patients who can be properly treated orthodontically from those who require orthognathic surgery. A large sample size was a necessary to obtain a sufficiently robust model. Thus, a multicentric study design was chosen (Orthodontic Departments of the Universities of Frankfurt, Heidelberg, and Würzburg, Germany). The cephalograms of 175 adult patients with Class III malocclusions were analyzed. The orthodontic group comprised 87 patients, and the surgery group, 88 patients. Twenty linear, proportional, and angular measurements were made. Stepwise discriminant analysis was applied to identify the dentoskeletal variables that best separate the groups. The discriminant function model was highly significant (P <.0001); 92% of the patients were correctly classified. The following variables were extracted: Wits appraisal, length of the anterior cranial base, maxillary/mandibular (M/M) ratio, and lower gonial angle. The resulting equation was: Individual score = -1.805 + 0.209. Wits + 0.044. S-N + 5.689. M/M ratio - 0.056. Go(lower). By means of discriminant analysis, correct classification of adult Class III malocclusion patients succeeded to a very high degree. Of all the variables, the Wits appraisal was the most decisive parameter.

Adult↗
PubMed2002

Prediction of arch perimeter changes due to orthodontic treatment.

A borderline orthodontic case with mild to moderate space deficiency can be treated without extractions. Expansion can be used to relieve space deficiency. The prediction of arch perimeter change for a given amount of expansion is helpful in planning the treatment of a patient who needs expansion, and it can facilitate nonextraction orthodontic treatment. To date, different amounts of arch perimeter change have been proposed for the same amount of expansion. A computer program is explained in this study, and examples of its uses are given. By entering 4 parameters of a dental arch into the computer program before and after an orthodontic procedure, one can simply calculate the total and the anterior arch perimeters and see the differences between them numerically and graphically. The program can save, print, change, and delete the calculated data for each patient. For clinicians who do not choose to use the computer program, 2 regression formulas are also presented to calculate the anterior and the total dental arch perimeters. The perimeters of 23 pairs of well-aligned dental arches were measured to check the accuracy of the computer program and the formulas. Paired t tests did not show statistically significant differences between the actual, the computer-derived, and the formula-derived perimeters of the dental arches at 95% confidence level.

Computer Graphics↗
PubMed2002

Evaluation of the peer assessment rating (PAR) index as an index of orthodontic treatment need.

The need for orthodontic treatment has an objective component based on occlusal traits and a subjective component based on the esthetic impact of the occlusion. An occlusal index that measures the objective deviation from normal or ideal occlusion might be sufficient to mirror the subjective opinion of orthodontists about treatment need. The objective of this study was to determine whether the American (US) and United Kingdom (UK) weightings of the peer assessment rating (PAR) index are valid instruments with which to determine treatment need. Fifteen orthodontists rated the need for orthodontic treatment of 170 casts. Their collective decision was compared with the PAR value for the cast determined by a calibrated examiner. A range of suggested treatment cutoff points from the literature was used to generate receiver operating characteristic (ROC) curves and optimized cutoff points. The cutoff points were 17 for both the US PAR and the UK PAR, and sensitivity, specificity, and kappa were 92%, 86%, and 0.77 for the US PAR and 92%, 89%, and 0.80 for the UK PAR. The area under the ROC curve was 97% for the US PAR and the UK PAR. Both the US PAR and the UK PAR scores were excellent predictors of orthodontic treatment need as determined by a panel of orthodontists. An occlusal index used to measure deviation from normal or ideal occlusion might perform as well as indexes of treatment need in predicting orthodontists' evaluations of treatment need.

Dental Occlusion↗
PubMed2003

Effect of sustained-release chlorhexidine varnish on Streptococcus mutans and Actinomyces viscosus in orthodontic patients.

This study evaluated the effect of sustained-release chlorhexidine varnish on orthodontic patients. Ten children, ages 10 to 16 years, participated. Bacterial levels of Streptococcus mutans and Actinomyces viscosus and total counts were evaluated in sputum samples. These counts were evaluated at 4 stages: before orthodontic treatment, at least 2 weeks after bonding of the brackets, 1 week after application of chlorhexidine varnish, and 3 weeks after application of chlorhexidine varnish. Increases in bacterial levels of S mutans and in the total bacterial count were detected after the brackets were bonded. One week after the sustained-release chlorhexidine varnish was applied, a significant decrease of total bacterial levels and S mutans was observed. This decrease persisted for 3 weeks after the first application. No significant change in A viscosus levels occurred during that period. The results provide additional evidence that sustained-release chlorhexidine varnish decreases S mutans levels in orthodontic patients with fixed appliances and therefore might be useful in preventing caries lesions.

Actinomyces viscosus↗
PubMed2003

In vivo inhibition of demineralization around orthodontic brackets.

Demineralization around orthodontic appliances is a problem. Suboptimal oral hygiene, long intervals between appointments, and potentially poor patient cooperation with using fluoride dentifrices and mouth rinses necessitate a compliance-free means of preventing tooth decay. The hypothesis of this study was that fluoride released by glass ionomer cement inhibits the formation of carious lesions around orthodontic brackets in vivo. Brackets were bonded on 2 first premolars in 21 randomized, consecutively selected patients 11 to 18 years old. Eleven test-group subjects were bonded with fluoride-releasing glass ionomer cement, and 10 control subjects were bonded with composite resin (no fluoride). The teeth were extracted after 4 weeks, sectioned, and evaluated quantitatively by cross-sectional microhardness testing. Fluoride levels in patient saliva were measured by the Taves diffusion method in samples taken at days 0 (baseline), 1, 2, 3, 7, 14, 21, and 28 to determine whether fluoride from the glass ionomer cement influenced the overall intraoral fluoride levels. The results demonstrated significantly more demineralization around the brackets of the control patients (P <.01, Wilcoxon signed rank test). For whole-mouth salivary fluoride levels, no significant overall difference between the groups (P >.05) and no noticeable trend within groups (P >.05) were found. These results indicate that using fluoride-releasing glass ionomer cement for bonding orthodontic brackets successfully inhibited caries in vivo. This cariostatic effect was localized to the area around the brackets and was statistically significant after 4 weeks.

Acrylic Resins↗
PubMed2002

Effect of a hydrophobic tooth coating on gingival health, mutans streptococci, and enamel demineralization in adolescents with fixed orthodontic appliances.

The effect of an anti-adhesive enamel coating on plaque accumulation, gingival health, and enamel demineralization was evaluated in 39 adolescents undergoing treatment with fixed orthodontic appliances using a prospective split-mouth design. Immediately after bracket insertion, the polymer was randomly applied after enamel etching to the buccal surfaces of the teeth in the left or right upper quadrant, leaving the opposite quadrant as an untreated control (218 test and 216 control teeth). Reapplications were carried out every 3rd month during the course or the study. The following data were collected at baseline and at designated follow-ups: visible plaque index, total viable counts and proportion of mutans streptococci in plaque samples, gingival bleeding index, and amount of gingival crevicular fluid. The incidence of enamel demineralization adjacent to the appliances was scored clinically at the termination of the orthodontic treatment. The observation time ranged from 6-24 months, during which the participants used fluoride rinses and toothpaste daily. A slightly impaired gingival health and increased levels or mutans streptococci compared with baseline was disclosed during the treatment. Five subjects showed enamel demineralization on a total of 30 teeth at the time of de-bonding. The results indicated no statistically significant differences between the enamel-coated and untreated teeth with regard to the studied variables at any follow-up. In conclusion, the present findings did not support a clinically beneficial effect of the polymeric tooth coating in a low-caries group of adolescents treated with fixed orthodontic appliances.

Acrylates↗
PubMedDate not supplied

Microdamage in porcine alveolar bone due to functional and orthodontic loading.

Bone remodelling has been associated with microdamage. The aim of this study was to investigate the presence of microdamage in the alveolar bone and its potential role in the initiation of bone remodelling following the application of an orthodontic load. The three-dimensional morphology of the alveolar bone was investigated by means of high resolution micro-CT scanning. In 25, 3-month-old, male Danish land-race pigs, the alveolar bone around the lower right and left first molars was analysed. The right first molar was moved buccally with a force of 130 cN by means of a custom-made cantilever made of a TMA 0.017 x 0.025 inch wire. The left molar was left untreated. After 1, 2, 4, 7 and 15 days of treatment the regions containing the right and left molars were excised and en bloc stained in basic fuchsin and the presence of microdamage detected. Diffuse damage was present in the alveolar bone of both the treated and the untreated teeth on both sides. On the lingual sides, diffuse damage showed the same orientation as the periodontal fibres. Bone microcracks were also detected on both the treated and untreated teeth. On the buccal surfaces they where often observed in close proximity to scalloped resorption surfaces. After 1 day of treatment, the presence of microcracks on the buccal-treated side was particularly marked. To conclude, bone microdamage is present in porcine alveolar bone in form of both microcracks and diffuse damage, suggesting that microdamage-driven remodelling also occurs in the alveolar bone. The presence of bone microcracks in the direction of the orthodontic force at day 1 suggests that they could represent the first damage induced by the orthodontic load that has to be repaired.

Animals↗
PubMed2003

Does caries prevention correspond to caries status and orthodontic care in 0- to 18-year-olds in the free public dental service?

The aim of the study was to evaluate the coverage of and time used for caries preventive actions by patient and by dentist's characteristics in relation to caries status and orthodontic treatments in patients from birth to 18 in public dental care in Helsinki City Health Department, Finland. Data on caries prevention for the age groups 0- to 18-year-olds in 1999 were analyzed in relation to patient age, caries status, orthodontic care, and dentist's characteristics. Our study comprised a total of 48,040 patients treated by 140 dentists. Main outcome measures were the coverage of and time used for repeated caries prevention performed during visits following the check-up visit. Nine percent of those under age 6 received repeated caries prevention, 29% of the 6- to 15-vears-olds and 24% of the 16- to 18-year-olds. Nineteen percent in the no-caries group (DMFT/dmft = 0) and 36% in the high-caries group (DMFT/dmft > 0 and DT + dt > or = 3) received repeated caries prevention. The average time a dentist used in repeated caries prevention was 3.6 min (s 3.1: median 2.8; range 0.2-15.4 min) for those in the no-caries and 8.1 (s 6.2; median 7.3; range 0.0-31.8 min) for those in the high-caries group. In each category of caries status, the average time used for repeated caries prevention was shorter for those not under orthodontic treatment. In conclusion, the variation in dentists' caries-preventive treatment practices is wide showing both over- and underuse of caries-preventive actions as judged by needs of patients.

Adolescent↗
PubMed1991

The effects of pregnancy and fluoride on orthodontic tooth movements in rats.

The present investigation was undertaken in order to study the velocity of orthodontic tooth movement in rats and the effect of the hormonal changes that occur during pregnancy or with fluoride, which is one of several trace elements that affect hard tissue metabolism. Adult, female Sprague-Dawley rats were separated into three groups: non-pregnant, pregnant, and non-pregnant NaF-supplied. All rats were treated with a fixed orthodontic appliance which moved the upper first molars in a buccal direction during 21 days. The appliances delivered an initial force of 150 mN. Repeated intra-oral, standardized radiographs were taken during the experimental period, and at the end of the experiment the maxillae were examined histologically. The velocity of tooth movement was calculated after measurement of the radiographs. The first molars were moved in a buccal direction in all groups. The mean value of the expansion from day 0 to 21 was significantly higher among the pregnant rats (0.64 mm) compared to the non-pregnant, control animals (0.46 mm) while the NaF-supplied rats had a significantly lower expansion (0.22 mm) compared to the control animals. In the histological examination of the pressure sides of the PDL of the upper first molars, the mean value of osteoclasts per microns x 10(-3) increased non-significantly in the group of pregnant rats and decreased significantly among the NaF-supplied animals compared to the non-pregnant control rats. The present experiment in rats indicated that the velocity of orthodontic tooth movement is influenced by hormones as well as trace elements.

Alveolar Bone Loss↗
PubMed1992

Mandibular function before orthodontic treatment.

Two-hundred-and-forty-five consecutive prospective orthodontic patients and 245 controls matched for age, sex, and residence, but with minor need of orthodontic treatment, were examined. The functional examination of the masticatory system was made according to Carlsson and Helkimo (1972), and Helkimo (1974). According to dysfunction index (Helkimo, 1974), 33.5 per cent of the patients and 21.6 per cent of the controls had a moderate, and 18.9 and 7.8 per cent respectively, a severe dysfunction. The corresponding figures for symptoms were 16.7 and 4.9 per cent respectively. In the patient group the frequency of signs and symptoms was higher in the older age group and in the girls. Orthodontic patients appeared to be at greater risk of craniomandibular disorders (CMD) than individuals with minor need of treatment.

Adolescent↗
PubMed1992

Need and demand for orthodontic treatment in an adult Swedish population.

The prevalence of malocclusion, the need for and the demand for orthodontic treatment was studied in a randomly selected adult Swedish population > or = 20 years of age. Nine-hundred-and-twenty subjects were examined of whom 669 had their own teeth in occlusion. From those a group of 157 subjects was selected on the basis of objective need and/or subjective demand for orthodontic treatment. The various regimens of treatment required in this group were investigated. The prevalence of malocclusion ranged from 17 to 53 per cent in the various age groups. The spectrum of malocclusion was similar to that previously reported in Swedish children. The awareness of their malocclusion was higher among younger than older subjects and among those who had severe malocclusion. Objective treatment need, evaluated by two experienced orthodontists, was estimated at 11 per cent of the total population, whilst orthodontic treatment was requested by approximately 5 per cent of the population studied.

Adult↗
PubMed1993

Orthodontic tooth movement into edentulous areas with reduced bone height. An experimental study in the dog.

The present study was performed in order to test the hypothesis that the height of supporting bone and connective tissue attachment will be maintained around teeth bodily moved into areas of reduced bone height. During a pre-experimental period, areas with markedly reduced bone height were produced in the mandible of 4 beagle dogs through extraction of the 4th premolars and subsequent surgical reduction of the bone height in the extracted sites to a level corresponding to half the root length of the 3rd premolar. Following healing, one of the third premolars was bodily moved in a distal direction into the area of reduced bone height, while the contralateral premolar served as a non-moved control. After 6 months of active tooth movement, the teeth were retained in their new position for a further 2 months before biopsies of test and control tooth sites were sampled. Radiographic evaluation showed that a bodily movement had been achieved with no or only minimal vertical displacement of the teeth. The histological analysis revealed that none of the teeth, orthodontically moved or not, had experienced loss of connective tissue attachment. Although a greater distance between the cemento-enamel junction and the bone crest was found on the pressure side of the orthodontically moved test teeth in comparison to the contralateral, non-moved control teeth, the bone level at all test teeth was more coronally positioned than the original, reduced bone level in the area into which the test teeth had been moved. Hence, these findings indicate that a tooth with a normal height of periodontal support can be orthodontically moved into an area of markedly reduced bone height with maintained height of the supporting apparatus.

Alveolar Bone Loss↗
PubMed1995

The repair of orthodontic root resorption: an ultrastructural study.

It has previously been shown by light (LM) and scanning electron microscopy (SEM), that after force is terminated, repair of the orthodontic root resorption lacunae occur by deposition of new cementum. The ultrastructural details of the process are not well established. Since it has been hypothesized that a new barrier to protect the root surface is formed during the reparative phase, new information on this aspect of orthodontic root resorption may be valuable. The aim of the present investigation was, by using transmission electron microscopy (TEM), to study in more detail the repair of orthodontic root resorption lacunae and the re-establishment of the adjacent periodontal membrane (PM). Three experimental tooth movement groups of rats (age 40-45 days) were used. The maxillary first molar was moved mesially by a closed coil spring for 10, 14, and 21 days. The results indicate that transition of active root resorption into a process of repair which occurs even in the presence of a light force, is associated with invasion of fibroblast-like cells from the circumference into the active root resorption site. After 10 days, formation of new tooth supporting structures was seen in the periphery of the resorption lacunae, while active resorption by multinucleated odontoclast-like cells (OD) took place in the central parts. In the later phases, after termination of force, the repair process is similar to the early cementogenesis occurring during tooth development. New mineralized cementum was observed on the resorbed root surface by 21 days. After deposition of the new cementum, the structures of a new periodontal ligament (PDL) were comparable with the control specimens.

Animals↗
PubMed1996

Orthodontic bonding with glass ionomer cement--a review.

Orthodontic bonding with glass ionomer cement is comparatively new. The purpose of this article is to review the current literature covering both in vitro and in vivo studies of various glass ionomer cements that have been used for orthodontic bonding. The review indicates that there is little support in the literature to suggest that the currently available conventional glass ionomer cements are suitable for routine clinical use in orthodontics. Dual- or tri-cured hybrid materials, however, comprising both glass ionomer and resin components, appear to have greater potential with regard to clinical performance.

Dental Bonding↗
PubMed1996

Orthodontic pre-treatment prior to autotransplantation of palatally impacted maxillary canines: case reports on a new approach.

Impacted maxillary canines in oblique horizontal positions may make orthodontic appliance treatment hazardous or impossible. Autotransplantation may be considered but the removal of the canine is often difficult and since atraumatic removal of the transplant is essential, autotransplantation is then impossible. A new possibility is orthodontic pre-treatment with distal and vertical traction of the impacted maxillary canine to bring the maxillary canine to a more favourable position and facilitate surgical removal and autotransplantation. Eight canines were surgically exposed and pre-treated prior to autotransplantation. Of 21 autotransplantations of maxillary canines, 20 were successful, among them all eight pre-treated cases. The orthodontic and surgical technique is described and illustrated in two case reports.

Adolescent↗