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PubMed2000

Maxillary and mandibular width changes studied using metallic implants.

The purpose of this implant study was to evaluate the transverse stability of the basal maxillary and mandibular structures. The sample included 25 subjects between 12 and 18 years of age who were followed for approximately 2.6 years. Metallic implants were placed bilaterally into the maxillary and mandibular corpora before treatment. Once implant stability had been confirmed, treatment (4 first premolar extractions followed by fixed appliance therapy) was initiated. Changes in the transverse maxillary and mandibular implants were evaluated cephalometrically and two groups (GROW+ and GROW++; selection based on growth changes in facial height and mandibular length) were compared. The GROW++ group showed significant width increases of the posterior maxillary implants (P <.001) and the mandibular implants (P =.009); there was no significant change for the anterior maxillary implants. The GROW+ group showed no significant width changes between the maxillary and mandibular implants. We conclude that (1) there are significant width increases during late adolescence of the basal mandibular and maxillary skeletal structures and (2) the width changes are related with growth potential.

Adolescent↗

PubMed1999

Stability and relapse of mandibular anterior alignment: University of Washington studies.

For more than 40 years, research in the Department of Orthodontics, University of Washington (Seattle, WA) has focused on a growing collection of more than 800 sets of patient records to assess stability and relapse of orthodontic treatment. All patients had completed treatment a decade or more before the last set of data. Evaluation of treated premolar extraction patients, treated lower incisor extraction patients, treated non-extraction cases with generalized spacing, patients treated with arch enlargement strategies, and untreated normals showed similar physiologic changes: (1) Arch length decreases after orthodontic treatment. (2) Arch width measured across the mandibular canine teeth typically reduces posttreatment, whether or not the case was expanded during treatment. (3) Mandibular anterior crowding during the posttreatment phase is a continuing phenomenon well into the 20-to-40 years age bracket and likely beyond. (4) Third molar absence or presence, impacted or fully erupted, seems to have little effect on the occurrence or degree of relapse. (5) The degree of post-retention anterior crowding is both unpredictable and variable and no pretreatment variables either from clinical findings, casts, or cephalometric radiographs before or after treatment seem to be useful predictors.

Adult↗

PubMed2004

Axiographic findings in patients undergoing orthodontic treatment with and without premolar extractions.

Mechanical axiography was performed on 49 (37 female, 12 male) patients prior to orthodontic treatment, after removal of the fixed appliance, and at the end of retention. Twenty-five subjects (mean age 12.8 years) underwent orthodontic treatment without premolar extractions (group 1) and 24 subjects (mean age 13.5 years) with premolar extractions (group 2). The axiographic tracings of the protrusive movements were analysed using a digitizer and specially designed software. A statistically significant increase (P < 0.05) in the values for horizontal condylar inclination (HCI) was found for both groups over the entire observation period. Group 1 showed a higher increase (P < 0.05) between the beginning of treatment and removal of the brackets, and group 2 between bracket removal and the end of retention. At the end of retention, a similar increase in HCI values was found for both groups. Over the observation period, the frequency of pathological axiographic findings decreased, which seems to be a positive effect of orthodontic treatment.

Adolescent↗

PubMed1996

Provision of orthodontic care to adolescents in South Australia: the type, the provider, and the place of treatment.

There are many pathways involving different providers and locations that individuals may take in obtaining, orthodontic services. The aim of this study was to document the provision of orthodontic services and establish the pathways taken toward fixed orthodontic treatment by adolescents in South Australia. Data were collected on the use of orthodontic services by a cohort of adolescents enrolled in the School Dental Service at age 13 years and again at age 15 years. By age 15 years, 83.2 per cent of the adolescents had received orthodontic consultations, 27.3 per cent had received fixed orthodontic treatment and 41.4 per cent had received other forms of orthodontic treatment (extractions, space retainers or removable appliances). The majority of fixed orthodontic treatment was supplied by orthodontists in the private sector, while extractions and removable appliances were provided mainly by public sector general dentists. Most individuals used services in both the public and private sectors and the most frequent pathway taken by the adolescents receiving fixed orthodontic treatment involved consultation in both the public and private sectors, non-fixed orthodontic treatment in the public sector and fixed orthodontic treatment in the private sector. The findings indicate wide access to orthodontic consultation and a high uptake of fixed orthodontic treatment once the adolescent sought private sector orthodontic consultation. Orthodontic care was seen to be an interactive process between public sector general dentists and private sector orthodontists.

Adolescent↗

PubMed1996

Orthodontic care in Sweden. Outcome in three counties.

The purpose of this series of studies was to evaluate the outcome of orthodontic care in Sweden from the professional's and the patient's perspective. In addition, a model was devised for the priority-planning of orthodontic care and for evaluating the different factors influencing the decision for orthodontic treatment. The results may be summarized as follows: Treatment Decision. Treatment desire, followed by treatment need and treatment benefit were the most important factors to consider when deciding whether or not treatment should be carried out. Regardless of the differences in resources and the structure of the free public care, a substantial proportion of the untreated 19-year-olds had malocclusions with treatment need, but they had no desire for treatment. Most of the 27-year-old individuals were satisfied with their earlier treatment decision, regardless of whether they had undergone orthodontic treatment. Dental professionals were considered to have had the greatest influence on this decision, which means that desire for treatment may be guided by the orthodontist. Individuals with malocclusions and treatment need--but who had refused proposed orthodontic treatment--were in general more discontented with their dental arrangement than other respondents, and a majority of them regretted their decision. Greater information to these individuals would have been desirable. Resources and Treatments Provided by General Practitioners or by Specialists. The sparsity of specialist resources resulted in either a greater restriction on the number necessary treatments being initiated or a greater proportion of the treatment being provided by general practitioners. In the 3 counties analysed, the treatment standard correlated well with the available resources: the greater the number of orthodontic specialists and ability to supervise the work of general practitioners and taking care of patients in need of specialist treatment, the higher the standard of treatment. Individuals treated by specialists were more contented than individuals treated by general practitioners. The measures of treatment outcome in general yielded more favourable scores for specialist treatments than for treatments provided by general practitioners, despite the specialist treatments on the average being classified as more difficult than those provided by general practitioners. Perceived treatment difficulty. About one-fourth of all treatments were classified as easy, one-fourth as moderately difficult, and one-half as difficult. The perceived treatment difficulty was associated on a group basis with the pretreatment need. The treatment investment increased and the treatment outcome became less favourable with increasing perceived difficulty. The treatment outcome was least favourable in the group where no treatment was suggested. Almost every fourth treatment was successfully carried out by mere extraction therapy. Attitudes in 27-year-olds. Orthodontic treatment was considered important by three out of four individuals, even in cases where irregularities of the teeth were small. A majority of the individuals thought that they would have been able to wear visible braces if needed, even in adult age. Methodological aspects. Studies that have used different indices to evaluate treatment outcome can only be compared with great caution. Measures with wide bases for evaluation may be more valid than measures with narrow bases. To estimate treatment outcome in terms of decrease of treatment need, the Indication Index may be recommended.

Adolescent↗

PubMed1997

The drum spring (DS) retractor: constant and continuous force for canine retraction.

Although much research has been undertaken on the rate of tooth movement, with different hypotheses having been put forward, the concepts of the threshold, light, heavy and optimal forces are not still clear. It has been stressed that an ideal orthodontic spring should have the ability to release a constant force throughout the entire range of its activation, but using traditional techniques applied initial force will decrease, depending on its deactivation due to the tooth movement and the physical properties of the force delivery system. The purpose of this study was to test the clinical use of a new and original spring, the drum spring (DS) retractor (developed in 1992), which applies a constant and continuous force without the need for reactivation, and to compare the effect of a constant and continuous force versus a continuous but diminishing force produced by a traditional pull coil (PC) retractor system on the rate of upper canine retraction. The clinical sample consisted of 15 patients with upper first premolar extractions. For each patient, the upper right canine was retracted by using a DS retractor applying a constant and continuous force of 50 g; the upper left canine was fitted with a conventional PC applying an initial force of 50 g, diminishing proportionally with the distal movement of the canine. In addition, each group was divided according to the age of each patient: eight patients (three males, five females) between 11.8 and 14.4 years of age (mean 13 +/- 1.2 years) represented the adolescent group, and seven patients (three males, four females) between 18.8 and 21.6 years of age (mean 18.2 +/- 1.9 years) representing the adult group. The experimental period started 1 week after the extraction of the first premolars. During this period no archwire was used, to avoid friction and force level changes, and the both springs were attached to a 6 mm hook fixed on the canine bracket to reduce tipping. The PC retractor was reactivated every 3 weeks whereas the DS retractor was left untouched over the entire experimental period. The study was continued until one of the two canines was completely retracted. The DS retractor was successful for space closure without any reactivation, and the continuous and constant force provided a more rapid canine movement than the continuous but diminishing force. Canine retraction occurred faster in adolescents than in adults. An entire field of clinical and research applications may be influenced by this new type of spring.

Adolescent↗

PubMed1988

First premolar extractions and fixed appliances in the Class II division 1 malocclusion.

This cephalometric study investigates the changes in the facial skeleton and dento-alveolar structures which occur during orthodontic treatment of the Class II Division 1 malocclusion by extraction of four first premolars followed by fixed appliances. The Begg and edgewise appliances are compared, and both are contrasted with a group of untreated Class II Division 1 subjects. The main effects of treatment were in the dento-alveolar structures, the changes in the overall facial pattern being small and largely due to extrusion of the molars during overbite reduction. Molar extrusion tended to interrupt forward growth rotation of the mandible, temporarily making it more backwards in direction, and increasing the lower anterior face height. An increase in the posterior lower face height was also noted in the edgewise group. Whilst SN A, and therefore AN B, reduced significantly during treatment, this was probably the result of palatal root torque to the upper incisors. The Begg appliance was more successful than edgewise in this respect.

Adolescent↗

PubMed1996

Treatment and postretention changes in dental arch width dimensions--a long-term evaluation of influencing cofactors.

The aim of the present long-term follow-up study of orthodontically treated patients was to analyze postretention changes in arch width dimension and to isolate factors that may serve as predictors of long-term prognosis. Pretreatment, end-of-treatment, and postretention (at least 10 years) models of 226 cases with different malocclusions were used to measure intercanine and intermolar width, arch length, sum of the mesiodistal dimension of the incisors, irregularity index, crowding, molar and canine relationship, overjet, and overbite. To assess the influence of initial and end-of-treatment alignment, kind of treatment (extraction versus nonextraction) and the amount of expansion in postretention stability, the sample was divided into different subgroups. The findings indicate that postretention arch width relapse occurred more frequently in the upper intermolar (25.8%) and lower intercanine region (23.9%) than in the lower intermolar (19.0%) and upper intercanine (13.8%) region. Pretreatment and posttreatment alignment as well as the kind of treatment and the amount of expansion were found to be influencing factors. The study concludes by proposing a reassessment of the definition of stability. The influence of the pretreatment anomaly, kind of treatment, amount of expansion, and posttreatment alignment on long-term stability should be recognized. Patients should be apprised of treatment limitations before treatments.

Adolescent↗

PubMed1996

Extraction of maxillary second molars in the treatment of Class II malocclusion.

The results of treatment following the extraction of maxillary second molars for Class II correction were evaluated. Records (cephalograms, orthopantomograms, and models) of 32 patients treated with maxillary second molar extraction were analyzed. Cephalograms taken before and after treatment were traced and 18 variables were compared. Changes in the axial inclination of the erupted third molars relative to the occlusal plane were measured on the orthopantomograms. The form and the position (eruption in occlusion, rotations) of the maxillary third molars were evaluated on the models. The average treatment time was 26 months. The results of this study show significant changes of the angles SNA, SNB, ANB, 1/4:SN, and the distances 1-NPog, and 1-APog, as well as significant effects on the soft tissue profile. In 19 cases examined 4 years postretention, all maxillary third molars had erupted into occlusion with a mesial contact point and acceptable mesiodistal axial inclination.

Adolescent↗

PubMed1986

A comparison of elastomeric auxiliaries versus elastic thread on premolar extraction site closure: an in vivo study.

Twenty-five patients requiring symmetric premolar extractions (representing eighty quadrants requiring canine retraction) were entered into the study. Standard 0.022 X 0.028-inch Siamese edgewise appliances with 0.016 X 0.022-inch arch wires were used during canine retraction. In 30 of the quadrants, canine retraction was accomplished with Unitek Alastik chain; 10 quadrants were treated with Rocky Mountain energy chain (medium). In the remaining 40 groups, canine retraction was accomplished via Unitek nylon-covered latex thread. The forces initially applied to the system were between 350-400 grams. Patients were seen at 3-week intervals to measure the amount of space closure and to change the elastic modules. A comparison among the three groups revealed no significant differences in rates of canine retraction (P less than 0.05). Empirically, the elastomeric auxiliaries were found to be more hygienic and required less chair time to apply than did the elastic thread.

Bicuspid↗

PubMed2002

Laser irradiation inhibition of open gingival embrasure space after orthodontic treatment.

The purpose of this study was to investigate the inhibitory effect of low-energy laser irradiation on an incidence of open gingival embrasure space after orthodontic treatment. The patient was a 20-year, 7-month-old Japanese female with an Angle Class I malocclusion and crowding in the mandible. Treatment consisted of extraction of maxillary and mandibular first premolars and use of the Edgewise technique. A Ga-Al-As diode laser was used to irradiate an area of 0.5 cm2 at the labial and lingual gingival papilla between the canines. The time of exposure was 6 minutes for 3 days, carried out between the relevelling and en masse stages of movement. The total energy corresponding to 6 minutes of exposure varied from 1.90 J/cm2. There was no further evidence of open gingival embrasure space, except at the mandibular central incisor. Further: an improvement in the gingival inflammation caused by a periodontal disease was observed, and periodontal pocket depth was maintained. These results suggest that low-energy laser irradiation may inhibit the incidence of open gingival embrasure space after orthodontic treatment.

Adult↗

PubMed1989

Profile changes in Class II, division 1 malocclusions: a comparison of the effects of Edgewise and Fränkel appliance therapy.

Changes in facial profile following orthodontic treatment were examined, using the lateral skull radiographs of 62 children exhibiting Class II, division 1 malocclusions and an average starting overjet in excess of 11 min. Thirty were treated by the extraction of upper first premolars and Edgewise mechanics whilst the remainder wore Fränkel appliances. Linear and angular measurements were made to record both soft tissue profile and the underlying dento-skeletal structures. In the Edgewise group, overjet reduction was accompanied by a 2.4 degree reduction in SNA together with distal movement of 'A' point and the upper incisor. At the same time both the nose and chin grew forwards. Despite good positioning of the lower incisor with respect to A-Po, both lips finished well behind the aesthetic plane and the resulting profile was undesirably retrusive. By contrast, the Fränkel appliance produced a more pleasing, well-balanced profile with a more ideal relationship of the lips to the aesthetic plane. Maxillary dento-skeletal structures maintained a more prominent position within the face whilst the mandibular structures moved actively forwards.

Activator Appliances↗

PubMed2005

Anchorage control in bioprogressive vs straight-wire treatment.

Orthodontic techniques with different concepts and philosophies have emerged to provide adequate anchorage control. The purpose of this study was to compare the effectiveness of the Bioprogressive and Straight-wire techniques in the control of lower anchorage. Data were obtained from the records of 40 patients presenting Class I and II malocclusions treated with first bicuspid extractions. One group of 20 patients was treated with a utility arch used to set up cortical anchorage in the lower arch and sectional retraction mechanics for space closure. The second group was treated with straight wire with a preadjusted appliance system. Treatment evaluation revealed no significant between-group differences in the amount of skeletal growth relative to cranial base and lower mesial movement of first molars. Mean lower anchorage loss was 3.1 mm in the Bioprogressive patients and four mm in the Straight-wire patients. The apical base change was the most important component to molar correction. Although cortical anchorage did not impede lower molar movement, it was no less effective in controlling molar movement with a partial appliance than was the fully banded Straight-wire appliance.

Adolescent↗

PubMed1998

Analysis of change in arch form with premolar expansion.

The arch forms of 38 cases (53 nonextraction and 23 extraction arches) in which expansion, while maintaining arch form, was the objective of the practitioner, were analyzed before treatment, after treatment, and an average of 6 to 8 years after retention. The cubic spline was used to fit a curve representing arch form. By superimposing the spline curves, changes in arch form were analyzed with the variables rebound change (RC), rebound index (RI), rebound number (RN), and stability number (SN). Traditional linear intraarch dimensions were also analyzed. Analysis of variance was used to determine differences between the maxillary and mandibular arches and between the extraction and nonextraction cases. Pearson correlation coefficients between spline variables and arch width variables were also computed. There was significantly more expansion in the maxillary arch than the mandibular arch during treatment, irrespective of extraction or nonextraction strategies. In the nonextraction cases, a greater amount of net expansion was achieved for all dimensions for the maxillary arch as compared with the mandibular arch. Overall, a relatively high stability in arch form was found. The findings suggest that stability may not be related to the amount of change produced during treatment. Significant expansion can be gained throughout the premolar regions and may be expected to be stable. The order of greatest net arch width gained was for the second premolars followed by first premolars, molars, and then the canines. The intercanine widths for both arches decreased toward pretreatment values, but were more stable in the maxillary arch in nonextraction cases. The cubic spline permits measurement of change in arch form both during treatment and retention periods.

Analysis of Variance↗

PubMed1985

Stability and relapse of mandibular anterior alignment: a cephalometric appraisal of first-premolar-extraction cases treated by traditional edgewise orthodontics.

Assessment at least 10 years postretention of fifty-four cases previously treated in the permanent-dentition stage with first-premolar extractions, traditional edgewise mechanotherapy, and retention revealed considerable variation among patients. The long-term response to mandibular anterior alignment was unpredictable; no cephalometric parameters, such as maxillary and mandibular incisor proclination, horizontal and vertical growth amounts, mandibular plane angle, etc., were useful in establishing a prognosis. Few associations of value were found between cephalometric parameters and dental-cast measurements, such as overbite, arch length, intercanine width, and overjet. Only a slight tendency was found for incisor inclination to return toward the pretreatment value during the postretention period. It was possible to predict, on the basis of an analysis of pre- and posttreatment cephalometric records, those cases which had greater than 4 mm deepening of overbite postretention as well as those cases which had decreases of 3 mm or more in arch-length postretention. The practical use of these predictions were of limited clinical value, however.

Adolescent↗

PubMed1989

Profile changes following orthodontic treatment of bimaxillary protrusion in adults with the Begg appliance.

Thirty-two adult oriental patients aged 18-26 years who sought treatment for their bimaxillary protrusion were treated with the Begg appliance following extraction of four first premolars. A cephalometric study was undertaken to determine the soft tissue changes in lip profile following treatment. Results show that the upper incisors were retracted by 5.6 mm +/- 0.8 mm and the lower incisors by 4.4 +/- 0.8 mm on the average. The nasolabial angle became more obtuse increasing from 80.7 degrees to 90.7 degrees. The upper lip and lower lip lengthened by 1.9 mm and 1.2 mm, respectively. The lower lip to 'E' line reduced from 7.5 mm to 3.7 mm. All the previous changes were statistically significant (p less than 0.01). The upper lip to upper incisor retraction was 1:2.2 while the lower lip to lower incisor retraction was 1:1.4. The correlation coefficients (r) were 0.72 (p less than 0.01) and 0.80 (p less than 0.01), respectively. The changes in the cants of mandibular and occlusal planes were statistically insignificant. This study shows that the Begg appliance has the ability to significantly reduce bimaxillary protrusions and thereby improve facial aesthetics.

Adolescent↗

PubMed1991

The effects of extraction and nonextraction treatment on the mandibular position.

Decisions on extraction of teeth as an aid in orthodontic treatment depend on dental and skeletal discrepancies concerning sagittal and vertical relationships. The purpose of this study was to assess the effects of extraction and nonextraction procedures on the posterior rotation of the mandible and the position of gnathion. Forty-eight nonextraction patients and seventy-three extraction patients treated in the orthodontic department were selected. The patients were from 11 to 15 years old, with a mean age of 12 years 2 months. The lateral cephalometric radiographs taken before and after treatment were traced and measured. Eleven variables reflecting the mandibular rotation were selected on the basis of factor analysis. Before treatment, total arch circumferential discrepancy and the 11 selected measurements showed significant differences between the extraction and nonextraction groups. In the extraction group, the lower anterior facial height was larger, ramus height was smaller, and the difference between vertical position of both maxillary and mandibular first molars and posterior facial height was greater than in the nonextraction group. Consequently, the mandible showed posterior rotation and was in retruded position in the extraction group. In the nonextraction group, the type of force application had no significant effect on the changes in skeletal and dental measurements. In the extraction group, however, the type of force application had a significant effect (p less than 0.05) on the changes in total anterior facial height, the horizontal distance of the maxillary first molar to a perpendicular line to the S-N plane passing through point S, the vertical distance of the maxillary molar to the S-N plane, the vertical distance of the maxillary and mandibular first molars to the S-N plane, the difference between the vertical position of the first molars and posterior facial height, and the difference between the vertical position of the first molar and vertical height of the ramus. In the group in which high-pull face-bow headgear was used, the extraction/nonextraction procedures had a significant effect (p less than 0.05) on the changes in angle ANB, total anterior facial height, anterior lower facial height, and the difference between anterior and posterior facial height.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1995

Changes in soft tissue profile of African-Americans following extraction treatment.

The purpose of this investigation was to determine changes in soft tissue profile of African-Americans following orthodontic treatment involving extraction of four premolars. The sample consisted of pretreatment and postreatment lateral cephalometric radiographs of 30 males and 30 females of African-American descent exhibiting bimaxillary protrusion. The age of the patients ranged between 10 years 4 months and 17 years 6 months at the start of treatment. Average time between pretreatment and postreatment radiographs was 2 years 11 months in the male group and 3 years 3 months in the female group. Changes in the dentofacial complex and facial soft tissue as a result of treatment and growth were evaluated with cephalometric analysis. Student's t-tests were performed to compare differences. Nasolabial angle increased 9.1 degrees in males and 7.1 degrees in females. Upper lip procumbency relative to SnPg' decreased 1.5 mm in males and 1.7 mm in females. Lower lip retraction relative to SnPg' was 2.7 mm in males and 2.5 mm in females.

Adolescent↗