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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↗

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↗

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↗

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↗

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↗

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↗

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↗

The effect of maxillary first premolar extraction and incisor retraction on mandibular position: testing the central dogma of "functional orthodontics".

It has been argued by a vocal coterie of disaffected dentists that premolar extraction, incisor retraction, and "backward-pulling" mechanics conspire to "distalize" the condyles and, pari passu, to produce craniomandibular dysfunction. Given the gravity of this conjecture, it seemed appropriate to test the predictions it generates in a sample of patients of the type most often said to be at risk: 42 "edgewise" patients with Class II, Division 1 malocclusions, treated in conjunction with the extraction of two maxillary first premolars. Regional and anterior cranial-base cephalometric superimpositions were used to quantify the individual components of the molar and overjet corrections, to measure both at the chin and condyles the mandibular displacement seen during treatment, and to examine the extent to which this displacement is related to the correction of maxillary incisor protrusion. Although the present patients underwent marked upper incisor retraction (on average, about 5 mm), lip retraction was much less pronounced, and 70% of the sample showed a net forward displacement of mandibular basal bone. Significantly, changes in condylar position were not correlated with incisor retraction, as the "functional orthodontists" would have it, but rather with the changes in the buccal occlusion and the growth of the maxilla. Thus, 30% of the patients who showed evidence of distal displacement were generally nongrowing patients who underwent more than average anchorage loss in the mandible and less than average loss in the maxilla.(ABSTRACT TRUNCATED AT 250 WORDS)

Activator Appliances↗

Cariostatic effect of glass ionomer retained orthodontic appliances. An in vivo study.

The cariostatic effect of a fluoride releasing bonding agent was investigated and compared with a conventional composite based material in connection with bonding of orthodontic brackets in 22 homologous pairs of premolars. All subjects had malocclusions requiring orthodontic treatment with fixed appliances and extraction of at least two premolars. 6-13 weeks prior to extraction, orthodontic brackets were bonded to the labial surfaces of the extraction teeth with either a glass ionomer cement or a bis-GMA resin. Initially, the children were instructed in tooth brushing and the regular use of fluoride. After extraction, the bonded teeth were stained and evaluated in a stereo-microscope regarding the incidence and extension of initial enamel demineralisation. The zone of intact enamel adjacent to the bracket base and bonding material was measured in a stereo-microscope at four predetermined locations with the aid of an electronic ruler and scored according to four categories. The incidence of enamel demineralisation adjacent to glass ionomer bonded and composite bonded brackets was 68% and 77% respectively. In 12 pairs of premolars however, the demineralisation appeared to a lesser extent on the enamel around the brackets was generally wider when glass ionomer cement was used compared to the composite resin. These differences were statistically significant (p < 0.05) mesially and distally, but non-significant cervically and incisally. The results indicate that bonding with glass ionomer cement may have a local cariostatic effect in children requiring fixed orthodontic appliances.

Adolescent↗

Evaluation of the vertical holding appliance in treatment of high-angle patients.

Controlling the vertical dimension of high-angle patients without the benefit of compliance can be a challenging aspect of orthodontic treatment. This retrospective study examines the skeletal and dental effects of a modified transpalatal bar, dubbed the vertical holding appliance (VHA), which was used in an attempt to control the vertical dimension of high-angle patients. Two cephalometrically similar groups of high-angle patients (16 patients each) were compared to determine advantages from using the VHA. Group I (n = 16, pretreatment age 13.4 +/- 1.6 years) was treated with 4 premolar extractions in conjunction with the VHA cemented in place for 17.4 +/- 6.1 months. Group II (n = 16, pretreatment age 13.4 +/- 1.9 years), which was matched for age and pretreatment skeletal pattern, was treated with the Tweed technique and 4 premolar extractions. Lateral cephalometric radiographs were taken before the placement of the VHA, as well as at the end of treatment. The results showed that although y-axis increased significantly in group II (P <.05), it remained the same in group I. Within group I, the Frankfort mandibular plane angle and gonion gnathion/sella nasion angle decreased, whereas both of these values increased in group II. However, these changes were statistically insignificant. Lower anterior face height increased more in group II than in group I (P <. 05). The percentage of lower anterior face height to total anterior face height decreased in group I, whereas it increased in group II. The difference between the 2 groups was determined to be significant (P <.01). Eruption of the maxillary first molar within group I was less than in group II. No significant differences were found between groups I and II for changes in overbite.

Adolescent↗

The effect of two contrasting forms of orthodontic treatment on the facial profile.

The purpose of this paper was to compare retrospectively the effect on the soft tissues of two contrasting forms of treatment for Class II, Division 1 malocclusion. The first group of 30 persons exhibited uncrowded dentitions and were treated without extractions by means of the Andresen activator. No other appliance was used. The second group was also composed of 30 persons. These subjects were treated with the Begg appliance in its classical form. All of the Begg subjects showed varying amounts of crowding and were treated by extraction of four first premolars. It was believed that the Andresen appliance would maintain the incisors in the most labial position possible, while the Begg group with premolar extractions would involve the maximum lingual incisal movement. These groups were compared with a third group of 22 untreated persons who also exhibited Class II, Division 1 malocclusions. The overjets in the treated groups were successfully reduced in both cases by retraction of the upper incisors; in the Begg group only, retraction of lower incisors was also performed. The upper incisors were retracted substantially more in the Begg group than in the Andresen group, but there was only a slight difference within the two groups in the final position of the upper lip relative to a vertical reference line through sella. There was also a slight difference in the lengths of upper and lower lips within the two treated groups. The lower lip followed the lower incisors more closely in the Begg group. Both upper and lower lips "uncurled" in the treated groups and this probably allowed them to be held together with little strain. There was a wide variation in individual response in all three groups.

Activator Appliances↗

Changes in occlusal force and occlusal contact area after active orthodontic treatment: a pilot study using pressure-sensitive sheets.

The aim of this study was to investigate functional changes in occlusion during retention. Data on occlusal force (OcFr) and occlusal contact area (OcAr) was obtained using the pressure-sensitive sheet, from a treated group (20 female patients) who had had four premolar extractions and treatment with standard edgewise appliances, and a control sample who matched the treated group of retainer for sex, age and Angle classification at 1 year after removal. A repeated measures analysis of variance showed that the mean values of total OcFr and OcAr in the treatment group gradually increased during retention and were 669.3 N and 15.1 mm2, respectively, at 1 year after removal of retainer. The increases of OcFr and OcAr were larger in the molar region, especially at the second molar. At 1 year after removal of retainer, OcFr and OcAr in the second molar were significantly larger in the treatment group than in the control sample, and a similar distribution pattern of OcFr and OcAr to those in normal occlusion was seen. These results suggested that balanced OcFr and OcAr might be obtained during and after retention, due to the settling of molars that had been discluded by active orthodontic treatment.

Adolescent↗

[DMF study on extracted deciduous teeth].

The aim of the present investigation was to study the number of the carious surfaces of extracted primary teeth in order to determine component m in the dmf-s index. Altogether 903 deciduous teeth were examined under artificial light with a dental probe. The surfaces were evaluated separately. The examined teeth were divided into two groups according to the amount of root resorption. On the basis of the present study the following conclusion can be drawn: 1. The average of df surfaces of molars was 2.34, whereas it was 0.74 at the front teeth. The df number shows practically only caries, because filled surfaces were found in only 1.99% of the cases. 2. In any type of the teeth df lesions were the rarest on the vestibular and oral surfaces. 3. Caries (filling) was found most frequently on the occlusal surfaces of the upper and lower 1st molars. Caries (filling was the rarest on the vestibular surfaces of the upper 1st and 2nd molars. 4. The amount of root resorption did not show much influence on the df score. 5. During the calculation of the dmf-s average of the primary teeth the m value can be substituted for 2.0.

Child↗

Prediction of maxillary third molar impaction in adolescent orthodontic patients.

The purpose of this study was to identify risk factors for maxillary third molar impaction in adolescent orthodontic patients. Radiographs made before treatment (T1) and after treatment (T2) and at a minimum of 10 years postretention (T3) of 132 patients that allowed accurate diagnosis of impaction vs eruption of one or both maxillary third molars were evaluated. Although univariate logistic regression revealed that the decision to extract premolars reduced the risk of impaction by 76% (P < .01), this parameter was not included in the final prediction model at T1. Multiple logistic regression analyses revealed that third molar impaction could be predicted at T1 according to the size of the retromolar space and the amount of mesial molar movement that will occur during active appliance therapy, reducing the risk of impaction by 22% and 34% for every millimeter increase in distance, respectively (P < .01). At T2, multiple logistic regression revealed that the odds of impaction were more than 60 times higher (P < .01) if the third molar was angulated mesially as compared with less than 30 degrees distally relative to the occlusal plane and almost five times (P < .05) higher if the third molar was angulated more than 30 degrees distally as compared with less than 30 degrees distally. Similar analyses at T2 showed 29% reduced risk of impaction for every millimeter increase in retromolar space and 18% reduced risk for every degree increase in angle MP/SN (P < .01).

Adolescent↗

Alkaline phosphatase activity in gingival crevicular fluid during canine retraction.

OBJECTIVES: The aim of the study was to investigate alkaline phosphatase activity in the gingival crevicular fluid (GCF) during orthodontic tooth movement in humans. SETTING AND SAMPLE POPULATION: Postgraduate orthodontic clinic. Ten female patients requiring all first premolar extractions were selected and treated with standard edgewise mechanotherapy. EXPERIMENTAL VARIABLE: Canine retraction was done using 100 g sentalloy springs. Maxillary canine on one side acted as experimental site while the contralateral canine acted as control. OUTCOME MEASURE: Gingival crevicular fluid was collected from mesial and distal of canines before initiation of canine retraction (baseline), immediately after initiation of retraction, and on 1st, 7th, 14th and 21st day and the alkaline phosphatase activity was estimated. RESULTS: The results show significant (p < 0.05) changes in alkaline phosphatase activity on the 7th, 14th and 21st day on both mesial and distal aspects of the compared experimental and control sides. The peak in enzyme activity occurred on the 14th day of initiation of retraction followed by a significant fall in activity especially on the mesial aspect. CONCLUSIONS: The study showed that alkaline phosphatase activity could be successfully estimated in the GCF using calorimetric estimation assay kits. The enzyme activity showed variation according to the amount of tooth movement.

Adolescent↗

Comparison of some effects of acetylsalicylic acid and rofecoxib during orthodontic tooth movement.

The purpose of this study was to examine the effects of 2 different anti-inflammatory drugs on gingival crevicular fluid (GCF) volume and on prostaglandin E(2) (PGE(2)) levels of the GCF during orthodontic tooth movement. A total of 36 extraction patients, aged 17.6 +/- 2.5 years (mean +/- standard deviation), were divided into 3 groups. Acetylsalicylic acid (aspirin) and rofecoxib (Vioxx, Merck, Whitehouse Station, NJ) were used for pain control in the first and second groups; the third group was used as a control. Gingival crevicular fluid was sampled at the beginning of tooth movement and at 24, 48, and 168 hours. An automated enzyme immunoassay was used to measure PGE(2) in GCF. The intragroup differences were evaluated with the Wilcoxon test, and the differences between the groups were determined with the Mann-Whitney U test. Gingival crevicular fluid volumes of the groups did not change significantly during the experimental period. Depending on the variations of fibroblast activation, PGE(2) levels of all the groups increased at 24 and 48 hours and decreased at 168 hours. When the drugs were compared, it was found that the inhibition effect of aspirin on PGE(2) was more than that of rofecoxib. The results suggest that rofecoxib can be used during orthodontic treatment, but further study is recommended.

Adolescent↗

A radiographic comparison of apical root resorption after orthodontic treatment with a standard edgewise and a straight-wire edgewise technique.

The purpose of this study was to compare the severity of apical root resorption occurring in patients treated with a standard edgewise and a straight-wire edgewise technique, and to assess the influence of known risk factors on root resorption incident to orthodontic treatment. The sample consisted of 80 patients with Angle Class II division 1 malocclusions, treated with extraction of at least two maxillary first premolars. Variables recorded for each patient included gender, age, ANB angle, overjet, overbite, trauma, habits, invagination, agenesis, tooth shedding, treatment duration, use of Class II elastics, body-build, general factors, impacted canines, and root form deviation. Forty patients were treated with a standard edgewise and 40 with a straight-wire edgewise technique, both with 0.018-inch slot brackets. Crown and root lengths of the maxillary incisors were measured on pre- and post-treatment periapical radiographs corrected for image distortion. Percentage of root shortening and root length loss in millimetres were then calculated. There was significantly more apical root resorption (P < 0.05) of both central incisors in the standard than in the straight-wire edgewise group. No significant difference was found for the lateral incisors. Root shortening of the lateral incisors was significantly associated with age, agenesis, duration of contraction period (distalization of incisors), and invagination, while root shortening of the central incisors was related to treatment group and trauma.

Adolescent↗

A comparison of outcomes of orthodontic and surgical-orthodontic treatment of Class II malocclusion in adults.

The treatment outcome for skeletal Class II malocclusion was reviewed in 33 nongrowing patients who were treated with orthodontics alone (by premolar extraction and tooth movement to camouflage the skeletal problem) and in 57 patients treated for similar problems with surgery and orthodontics (with mandibular advancement and with tooth movement to reduce rather than increase dental compensation for the skeletal deformity). Cephalometric and dental cast changes were scored to quantitate treatment effects. Two approaches were used to determine the treatment efficacy (the relative success of treatment): (1) whether the final value for a measurement criterion (such as an overjet and an ANB angle) fell within the normal range, and (2) the quantitative amount of correction produced relative to an "ideal" value. In addition, a panel of judges was used to rate esthetic changes from pretreatment and posttreatment facial slides. Both orthodontic treatment and surgical-orthodontic treatment improved the malocclusion as judged from dental casts. Surgery resulted in greater reduction of overjet and greater improvement in most cephalometric skeletal, dental, and soft tissue criteria. Before treatment, the surgical patients had lower esthetic ratings than the orthodontics-only patients. After treatment, the esthetic ratings for the orthodontic patients were unchanged. The surgical patients had improved but not to the pretreatment level of the orthodontics patients.

Adult↗