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The purpose of this investigation was to evaluate a unique sample of orthodontically treated subjects ( N = 114; post-retention = 11.97 years). All subjects were treated by one clinician utilizing a consistent diagnostic and treatment protocol. Subjects were grouped into two distinct groups according to the lower incisor irregularity: group 1, "moderate change" and group 2, "minor change." Statistical analyses were performed at a level of r ≥0.6, p 2 ), posterior face height (at T 2 ), the mandibular plane angle SN-GoGn (at T 2 ), anterior crowding (at T 2 ), and starting age (at T 1 ). It is clearly noted that the vertical dimension features in the equation.

The treatment effects and the short-term (0.9 +/- 0.45 years) relapse potential of phase I slow maxillary expansion, with a bonded palatal expander or a quad-helix appliance combined with a mandibular banded Crozat/lip bumper and followed by 12 to 15 months of retention, were examined.Pretreatment (8.8 +/- 1.7 years) and posttreatment (11.1 +/- 1.7 years) models of 54 patients were used to evaluate treatment effects. Posttreatment (11.0 +/- 1.3 years) and follow-up (11.9 +/- 1.4 years) models of 23 patients who returned for phase II treatment were used to evaluate relapse over the 11 months, during which no retention was used. The models were digitized, and 15 measures were computed.Significant treatment increases were observed for all measurements in both arches. Treatment gains in arch perimeter (6%-8%) were due more to increases in intermolar width (11%-15%) than to increases in arch depth (5%). Posttreatment relapse was significant (P.05) for all measures except mandibular intercanine width and maxillary molar arch depth. After accounting for normal growth, net changes (pretreatment to follow-up) indicated significant increases for all measures except maxillary molar arch depth. In addition to maintaining leeway space, the maxilla and the mandible showed net perimeter gains of 2.9 and 1.0 mm, respectively.Slow maxillary expansion combined with a mandibular banded Crozat/lip bumper during the early mixed dentition produced clinically useful increases in arch dimensions that subsequently underwent mild-to-moderate amounts of relapse after removal of all retention appliances.

The purpose of this investigation was to determine the long-term differences in soft tissue profile changes between extraction and nonextraction patients who had been treated to the same incisor position and lip line.Twenty extraction and 20 matched nonextraction patients, with posttreatment and long-term follow-up (average 15 years) records, were selected from a single private orthodontic practice. Posttreatment and long-term follow-up profile photos of the patients' nose, lip, and chin areas were evaluated by 105 orthodontists and 225 laypeople, who indicated their preferences and the amount of change they perceived among the 40 profiles. The patients had similar dental protrusion, soft tissue profile measurements, and ages at the posttreatment observation.No significant cephalometric differences between the extraction and nonextraction groups were found at long-term follow-up; both groups showed similar long-term changes. Significant (P.05) differences were found between males and females at long-term follow-up; male lips became relatively more retrusive, and their profiles became flatter. Significant (P.05) changes in the profiles were also perceived over time, but there was no relationship between the amount of change perceived and profile changes measured cephalometrically. There were also no significant (P.05) differences in preferences between orthodontists and laypeople, between extraction and nonextraction patients, or between males and females.If extraction and nonextraction patients are treated to the same incisor position and lip line, the treatment modality does not affect long-term soft tissue profile changes. Furthermore, the amounts of change perceived by either orthodontists or laypeople were not related to the amount of change measured cephalometrically.

The purpose of this study was to evaluate the long-term postretention stability of rapid palatal expansion-lip bumper therapy followed by full fixed appliances.The sample included 20 treated patients (11 women and 9 men) who were recalled to obtain postretention records. The subjects were out of retention for a minimum of 4 years and an average of 7.9 years. They had begun treatment in the late mixed dentition at a mean age of 11.1 with considerable incisor crowding but, on average, no tooth size-arch length discrepancies. Pretreatment, posttreatment (mean age, 13.6 years), and postretention (mean age, 24.3 years) models were digitized, and the computed measurements were compared with untreated reference data.The majority of treatment increases in maxillary and mandibular arch dimensions were statistically significant (P.05) and greater than expected for untreated controls. Although many measurements decreased postretention, net gains were maintained for 21 of the 30 measurements evaluated. The notable exception was arch perimeter, which decreased to less than pretreatment values. Postretention incisor irregularity increased 0.5 +/- 1.2 mm in the maxillary arch and 1.1 +/- 1.5 mm in the mandibular arch.Based on the good long-term stability observed in this study, we concluded that use of rapid palatal expansion-lip bumper expansion therapy in the late mixed dentition followed by full fixed appliances is an effective form of treatment for patients with up to moderate tooth size-arch length discrepancies.

The aim of this study was to assess the impact of various sized buccal corridors (BCs) on smile attractiveness. One female smiling photograph, displaying first molar to first molar (M1–M1), was digitally altered to produce (1) smiles that filled 84, 88, 92, 96, and 100 per cent of the oral aperture; (2) second premolar to second premolar smiles (PM2–PM2) that filled 84, 88, 92, and 96 per cent of the oral aperture; and (3) smiles with asymmetrical BC that filled 88, 90, 94, and 96 per cent of the oral aperture. The 18 smiles produced were evaluated by 82 orthodontists (70 males and 12 females) and 94 laypeople (40 males and 54 females). Paired t -tests were used to evaluate differences within the orthodontist and laypeople groups: independent t -tests were used to compare the two groups. The effect of age and gender on the ratings was evaluated by two-way analysis of variance. Orthodontists and laypeople rated smiles with small BCs as significantly ( P < 0.05) more attractive than those with large BCs. Orthodontists rated M1–M1 smiles as more attractive than PM2–PM2 smiles, whereas laypeople preferred PM2–PM2 smiles. Orthodontists rated only two of eight asymmetrical smiles as less attractive than would be expected for symmetrical smiles with similar arch widths; laypeople did not rate any asymmetrical smiles as less attractive than would be expected. Rater age and gender did not significantly influence the impact of BCs on smile attractiveness.

One of the most common problems in orthodontics is tooth size-arch length discrepancy (TSALD). The controversy over whether to resolve this discrepancy by increasing the size of the dental arch or by reducing the amount of tooth structure persists to this day. Because virtually any approach to resolving TSALD can align the teeth, the long-term stability of competing approaches is of paramount importance. The effect on the face is also a major consideration. Of the various aspects of occlusion such as molar relationship, overbite, and overjet, mandibular anterior alignment is the area of relapse most noted by patients. Therefore, it has been the focus of many stability studies. The most common unit of measurement for mandibular anterior tooth alignment is the irregularity index as suggested by Little in 1975. The irregularity index is defined as the sum of the distance between the contact points of the 6 permanent anterior teeth. It is not the same as TSALD. An irregularity index of less than 3.5 mm is judged to be minimal and thus clinically satisfactory. An irregularity index score greater than 6.5 mm indicates severe irregularity. There are few reports in the literature on long-term postretention stability of TSALD patients treated in the mixed dentition. Four studies at the University of Washington reported on both approaches—increasing arch length and extracting premolars. The study of resolving the TSALD in the mixed dentition by increasing arch length (expansion) was especially discouraging. Seven and a half years postretention, 89% of the patients studied had unsatisfactory results, with a mean irregularity index score of 6.06 mm. The 3 studies in which premolars were extracted in the mixed dentition found an irregularity index 10 years postretention of 4.39, 3.15, and 3.09 mm, respectively. Foster and Wiley found that extraction of deciduous canines had no detrimental effect on the eventual width of the permanent canines. Numerous studies have documented that mandibular incisors tip lingually as a result of serial extraction, but not excessively. So, is extracting in the mixed dentition, followed by multibanded treatment in the permanent dentition and a retention phase of approximately 3 years, a better choice in the long term? In one study, researchers examined a subsample of 30 serial extraction patients from the 114 studied by Scott Franklin in his 1995 “AAO Award of Merit” thesis. The subsample included 8 males and 22 females with a mean T1 age of 10.44 years and a mean postretention (T3) age of 30.3 years. T2 records were collected shortly after the end of active treatment. Long-term postretention crowding in these serial extraction patients was minimal. The mean T3 irregularity index of 2.7 mm was below the cut-off level of 3.5 mm considered to be satisfactory. The range was 0.31 to 5.9 mm, and 70% of the patients were in the minimally irregular category, and none was in the severe category (over 6.5 mm). Evaluation of the facial profiles at the end of treatment and 15 years later by using the Holdaway line showed that profiles were within the normal range at both periods. Numerous studies have found that premolar extractions do not produce poor facial balance. In her thesis at the University of Toronto, Julianne Peterson found similar results. She examined 20 serial extraction patients (3 males and 17 females) with a mean T1 age of 10.5 years and a mean postretention age of 30.8 years. Nearly 16 years posttreatment, the mean T3 irregularity index score was 2.4 mm (range, 0.5 to 4.95 mm). Seventy-five percent of the patients fell into the minimal category, and none was severe. In these stable cases, the mandibular intercanine expansion was minimal (1.2 mm), and the mandibular Associate professor, Baylor College of Dentistry, Texas AM Phoenix, Ariz. Am J Orthod Dentofacial Orthop 2002;121:575-7 Copyright © 2002 by the American Association of Orthodontists. 0889-5406/2002/$35.00 0 8/1/124685 doi:10.1067/mod.2002.124685