Treatment outcomes after extraction and nonextraction treatment evaluated with the American Board of Orthodontics objective grading system

doi:10.1016/j.ajodo.2014.07.025

American Journal of Orthodontics and Dentofacial Orthopedics

Volume 146, Issue 6, December 2014, Pages 717-723

https://doi.org/10.1016/j.ajodo.2014.07.025 Get rights and content

Highlights

•
We found no statistically significant differences between 8 variables and total ABO-OGS scores.
•
Treatment modality, age, or sex did not significantly predict successful ABO examinations.
•
Buccolingual inclination appeared to complicate orthodontic treatment the most.

Introduction

A controversy exists regarding better treatment outcomes when patients treated with extractions and without extractions are evaluated. The aims of this study were to use the American Board of Orthodontics objective grading system (ABO-OGS) to evaluate and compare treatment outcomes in extraction vs nonextraction Class I patients and to determine whether the treatment choice was a significant predictor of success according to the ABO examination.

Methods

Discriminant analysis was applied to a sample of 542 patients, and a borderline sample of 55 patients was obtained. Of these patients, 25 were treated with extractions and 30 without extraction of the 4 first premolars. Treatment results were then assessed using the 8 variables of the ABO-OGS.

Results

The total scores ranged from 11 to 41 (mean, 27.04; SD, 6.3) for the extraction group and from 16 to 44 (mean, 29.07; SD, 7.1) for the nonextraction group. The variable of buccolingual inclination had the highest scores in both groups (8.44 [SD, 3.3] for the extraction group; 8.90 [SD, 3.8] for the nonextraction group; mean difference, 0.46; 95% CI, −1.44, 2.37; P = 0.63). However, no statistically significant intergroup differences were found, either between the scores of the 8 ABO-OGS variables or between the total ABO-OGS scores. Regarding the success rates of the ABO examination, no significant difference was found between the 2 treatment groups (odds ratio, 2.55; 95% CI, 0.74, 0.85; P = 0.14).

Conclusions

For a patient with a borderline Class I malocclusion, extraction and nonextraction treatment can achieve the same quality of results as assessed by the ABO-OGS. Additionally, in these Class I patients, the treatment modality (extraction or nonextraction) is not a significant predictor of passing the ABO examination.

Section snippets

Material and methods

In this retrospective study, the parent sample consisted of the records of 542 patients gathered from 5 private orthodontic practices and from the University of Athens graduate orthodontic clinic in Greece. The inclusion criteria for the parent sample were white male or female patients with a Class I dental and skeletal malocclusion, a full complement of teeth excluding the third molars, no previous orthodontic treatment, no clefts or dentofacial deformities, and no orthognathic surgery

Results

The results of descriptive and inferential statistics calculated for the ABO-OGS variables are shown in Table IV. The total scores for the extraction group ranged from 11 to 41, with a mean value of 27.04; the scores for the nonextraction group ranged from 16 to 44, with a mean value of 29.07. No statistically significant difference was observed in the total ABO-OGS scores between patients treated with or without extractions (mean difference, 2.03; 95% confidence interval (CI), −1.60, 5.65; P

Discussion

Often in the literature, comparisons of 2 treatment modalities are contaminated with “susceptibility bias,” which is defined as a between-groups or among-groups difference in prognostic expectations for the treatment outcome. The innovative aspect of our study was the objective way of defining a bias-free borderline sample via discriminant analysis. To achieve an accurate representation of all patients' attributes, 34 variables were used in the discriminant analysis. Then a borderline sample

Conclusions

The results of this investigation showed no statistically significant differences in the total ABO-OGS scores between Class I patients treated with and those treated without extraction of the 4 first premolars. Although the extraction group, in general, achieved better scores, no statistically significant differences were found between scores of the 8 ABO-OGS variables. The variable of buccolingual inclination, through which torque control of the posterior segments is assessed, received the

References (23)

S.E. Bishara et al.
Treatment and posttreatment changes in patients with Class II, Division 1 malocclusion after extraction and nonextraction treatment
Am J Orthod Dentofacial Orthop
(1997)
P.E. Rossouw et al.
A longitudinal evaluation of extraction versus nonextraction treatment with special reference to the posttreatment irregularity of the lower incisors
Semin Orthod
(1999)
J.R. Beattie et al.
The functional impact of extraction and nonextraction treatments: a long-term comparison in patients with “borderline,” equally susceptible Class II malocclusions
Am J Orthod Dentofacial Orthop
(1994)
D.W. Cassidy et al.
A comparison of surgery and orthodontics in “borderline” adults with Class II, division 1 malocclusions
Am J Orthod Dentofacial Orthop
(1993)
F.A. Livieratos et al.
A comparison of one-stage and two-stage nonextraction alternatives in matched Class II samples
Am J Orthod Dentofacial Orthop
(1995)
C.L. Campbell et al.
Treatment outcomes in a graduate orthodontic clinic for cases defined by the American Board of Orthodontics malocclusion categories
Am J Orthod Dentofacial Orthop
(2007)
E.T. Chaison et al.
The quality of treatment in the adult orthodontic patient as judged by orthodontists and measured by the objective grading system
Am J Orthod Dentofacial Orthop
(2011)
D.R. Cook et al.
Comparison of university and private-practice orthodontic treatment outcomes with the American Board of Orthodontics objective grading system
Am J Orthod Dentofacial Orthop
(2005)
Y.B. Pinskaya et al.
Comprehensive clinical evaluation as an outcome assessment for a graduate orthodontics program
Am J Orthod Dentofacial Orthop
(2004)
G.Y. Song et al.
Validation of the American Board of Orthodontics objective grading system for assessing the treatment outcomes of Chinese patients
Am J Orthod Dentofacial Orthop
(2013)

L.C. Yang-Powers et al.

Treatment outcome in a graduate orthodontic clinic using the American Board of Orthodontics grading system

Am J Orthod Dentofacial Orthop

(2002)

Cited by (18)

Palatal shape covariation in extraction versus nonextraction borderline patients: A geometric morphometric study
2023, American Journal of Orthodontics and Dentofacial Orthopedics
This study aimed to evaluate changes in palatal shape after orthodontic treatment from a borderline sample of extraction and nonextraction patients with a Class I relationship.
A borderline sample regarding premolar extractions was obtained through discriminant analysis and comprised 30 nonextraction and 23 extraction patients. The digital dental casts of these patients were digitized with 3 curves and 239 landmarks placed on the hard palate. Procrustes superimposition and principal component analysis were implemented to assess group shape variability patterns.
The success of the discriminant analysis in identifying a borderline sample regarding the extraction modality was validated using geometric morphometrics. Concerning palatal shape, no sexual dimorphism was found (P = 0.78). The first 6 principal components that were statistically significant accounted for 79.2% of the total shape variance. Palatal changes were 61% more pronounced in the extraction group, which exhibited a decrease in palatal length (P = 0.02; 10,000 permutations). In contrast, the nonextraction group showed an increase in the palatal width (P <0.001; 10,000 permutations). Intergroup comparisons indicated that the nonextraction group exhibited longer palates, whereas the extraction group exhibited higher palates (P = 0.02; 10,000 permutations).
Considerable changes in palatal shape were seen for the nonextraction and extraction treatment group, with the latter exhibiting more pronounced changes, mainly in terms of palatal length. Further investigations are needed to clarify the clinical significance of the palatal shape changes in borderline patients after extraction and nonextraction treatment.
Dental, skeletal, and soft-tissue changes in adult orthodontic patients treated with premolar extraction and nonextraction: A cross-sectional study
2022, American Journal of Orthodontics and Dentofacial Orthopedics
Citation Excerpt :
These findings are in concurrence with the literature.16 Anthopoulou et al,17 when comparing borderline patients treated by PME and NE, found that while PME scored less for ABO-OGS, the difference was statistically insignificant for the total score and all the components. A contrast in these findings can be explained because of the selection of patients.
Various treatment modalities exist to improve and correct Class I malocclusion. This study evaluated the dental, skeletal, and soft-tissue changes in patients treated by premolar extraction (PME) and nonextraction.
A cross-sectional study was conducted, including subjects ideally planned for PME. Pretreatment and posttreatment lateral cephalograms were compared among the 2 groups. The American Board of Orthodontics Objective Grading System (ABO-OGS) was used to score the posttreatment casts, and soft-tissue profile silhouettes were judged by a panel of orthodontists to evaluate the improvement among the 2 groups. Comparisons between the 2 groups were performed using the Mann-Whitney U test. Spearman correlation was used to study the correlation between the assessment methodologies.
Highly significant differences were observed between the 2 groups for ABO-OGS scores (P ≤0.001) and profile silhouette assessment (P ≤0.001). Compared with posttreatment cephalometric readings, highly significant differences were seen for the dental variables: SN-U1, IMPA, and interincisal angle (P ≤0.001). Statistically significant differences were seen for all soft-tissue cephalometric variables. Highly significant moderate to negative correlation (r = −0.410, P ≤0.001) was seen between profile silhouettes and ABO-OGS alignment scores. Highly significant strong negative correlation (r = −0.642, P ≤0.001) was seen between profile silhouettes and the lower lip.
Dental and soft-tissue changes were highly significant and were found to be in the ideal range when treated with PME. However, PME and nonextraction treatment modalities did not significantly affect the skeletal parameters as seen on the lateral cephalogram.
Stability of first and second premolars extraction space closure
2022, American Journal of Orthodontics and Dentofacial Orthopedics
Citation Excerpt :
Results were considered significant at P <0.05. The random errors were within acceptable limits,27,36 and there were no statistically significant systematic errors (Table I). The groups were comparable regarding initial, final, and follow-up ages, initial and final occlusal statuses, treatment and posttreatment times, maxillary and mandibular crowding, occlusal quality at the finishing and follow-up stages, sex, and malocclusion types distribution (Table II).
Premolars are the teeth most often extracted to provide space to correct crowding, excessive dental and/or labial protrusion, and to compensate for the sagittal discrepancy. After treatment, the extraction spaces have to remain closed. Nevertheless, several studies have shown a tendency for some relapse even in patients finished with an adequate occlusion. Thus, the objective of this study was to compare the stability of extraction space closure of the first and second premolars.
Dental casts of 72 patients were digitized using a 3-dimensional scanner (R700; 3Shape, Copenhagen, Denmark) and divided into 2 groups. Group 1 (29 patients; mean age, 13.79 years; 4.57 years after treatment; 116 extraction spaces) was treated with first premolar extractions, and group 2 (43 patients; mean age, 15.20 years; 3.97 years after treatment; 100 extraction spaces) was treated with second premolar extractions. Chi-square tests were used to compare the numbers of open and closed extraction spaces after treatment and at the long-term posttreatment stage. t Tests were used to compare the number of spaces posttreatment and at the long-term posttreatment stages. These tests were also performed in subgroups with completely closed extraction sites posttreatment.
The groups showed similar numbers of extraction sites reopening. The first and second premolar extraction space closure presents a similar tendency for reopening. Considering only the patients that showed completely closed extraction spaces in the final dental models, maxillary extraction space reopening was larger in the first premolar extraction group.
First and second premolar extraction space closure present similar stability.
Accuracy of dental arch form in customized fixed labial orthodontic appliances
2022, American Journal of Orthodontics and Dentofacial Orthopedics
This study evaluated arch form accuracy with or without premolar extraction in customized fixed labial orthodontic appliance treatment.
Setup and posttreatment digital models of 27 samples (15 extractions and 12 nonextractions) were selected and superimposed by best-fit surface-based registration in both the maxilla and the mandible. The facial axis points were identified and converted into Cartesian coordinates. A sixth-order polynomial equation was used to fit dental arches. Arch discrepancies (the mean distance between 2 arch forms) and similarities were compared between extraction and nonextraction groups, maxilla and mandible, and anterior and posterior arches.
The arch discrepancy between extraction and nonextraction groups showed no statistically significant difference, but a statistically significant difference in arch similarity was found in the mandible. There were statistically significant differences between anterior and posterior arch discrepancies in the extraction (mandible) and the nonextraction (maxilla and mandible) groups. However, no statistically significant correlation was shown between anterior and posterior arch discrepancies. The arch similarities were 96.18% and 97.38% in the maxilla and 96.01% and 97.49% in the mandible between extraction and nonextraction groups. Arch form discrepancies and similarities showed a moderate correlation but no statistically significant differences between the maxilla and the mandible.
In customized fixed labial orthodontic appliance treatment, arch form setup can be accurately achieved with and without premolar extraction. Anterior arch form acquires fewer discrepancies than the posterior arch, and overcorrection should be added to the end of the customized archwire to reduce posterior arch discrepancies. The discrepancy of the maxillary and mandibular arches is interrelated, and adjustments should be made on both maxillary and mandibular archwires to correct single-jaw transverse malposition.
Long-term occlusal changes and patient satisfaction in patients treated with and without extractions: 37 years after treatment
2020, American Journal of Orthodontics and Dentofacial Orthopedics
Citation Excerpt :
The buccolingual inclination is related to torque control in posterior segments. Some studies show high scores for these criteria, illustrating the tendency for deficiency in placing adequate torque in the buccal segments.30,38 Furthermore, some authors6,51 also found that buccolingual inclination tends to deteriorate over time with the natural aging process.
The objective of this research was to evaluate the treatment outcomes, long-term occlusal changes, and patient satisfaction after 37 years of nonextraction and extraction treatments.
Fifty-seven patients with Class I and Class II malocclusion were divided into 2 groups. Group 1 included 16 patients treated with nonextraction therapy, with mean initial (T1), final (T2), and long-term posttreatment (T3) ages of 13.2, 15.0, and 50.3 years, respectively. Mean treatment time (T2 – T1) and long-term follow-up time (T3 – T2) were 1.8 and 35.2 years, respectively. Group 2 included 41 patients treated with extraction of 4 first premolars, with mean ages at T1, T2, and T3 of 13.3, 15.6, and 53.6 years, respectively. Mean treatment (T2 – T1) and long-term follow-up (T3 – T2) times were 2.3 and 37.9 years, respectively. The Peer Assessment Rating (PAR) index and Objective Grading System (OGS) indexes were evaluated at T1, T2, and T3 stages. The subjects also answered an online questionnaire regarding esthetic and occlusal self-perception at T3. Intergroup comparison was performed with t tests.
The PAR index improved with treatment and similarly worsened at T3 for both groups. OGS scores were close to the passing score at T2 for both groups. The nonextraction group presented worse OGS scores at T3 than the extraction group. Nonextraction patients perceived more changes in alignment over time, but overall satisfaction was similar.
The PAR index improved with treatment, and the PAR and OGS scores showed a significant increase, indicating great occlusal changes in the long-term stage. The nonextraction group showed more occlusal changes and perceived more changes in their alignment over time, but overall patient satisfaction was similar in both groups.
Long term stability of treatment outcome after fixed orthodontic treatment with or without premolar extraction
2019, Orthodontic Waves
Citation Excerpt :
These findings indicated that occlusion remained stable over a period of two years after the post-treatment and there was no difference between the extraction and non-extraction treatment plan. The findings are in agreement with the study of Anthopoulou et al. [29] and Akinci Cansunar and Uysal [30] who also reported that an acceptable occlusion could be achieved at the post-treatment in the patients treated with either of the treatment philosophy i.e. extraction or non-extraction whereas Farhadian et al. [28] found that the patients who had undergone extraction of four premolars had more acceptable final occlusion. There was significant relapse in crowding of maxillary and mandibular anterior teeth in both extraction and non-extraction groups.
To evaluate and compare the long term stability of treatment outcome in patients treated with fixed orthodontic treatment with and without premolar extractions.
Fifty five debonded patients (35 females and 20 males) with complete pre-treatment (T0) and post-treatment (T1) records with at least 3 years of post-retention (T2) were included in the study. These patients were divided into two groups; Extraction group comprising of 30 patients who had undergone 4 premolar extractions and non-extraction group had 25 patients. Long term stability of post-treatment occlusion was assessed with Little’s irregularity index, intercanine width and ABO model grading system.
The incisor irregularity score increased in both extraction and non-extraction groups from post-treatment (T1) to post-retention (T2) and the mean changes were statistically significant. The results of Mann–Whitney test for Little’s irregularity index and intercanine width showed no statistically significant differences between the extraction and the non-extraction groups at T1 to T2. The overall mean changes in the ABO variables showed no statistically significant differences (P > 0.05) from post-treatment (T1) to post-retention phase (T2) in extraction and non-extraction groups except interproximal contacts, which showed a statistically significant difference.
There was significant relapse in the alignment of maxillary and mandibular anterior teeth with a change in Little’s irregularity score, intercanine width and ABO scores from post-treatment to post-retention. The comparison of relapse in extraction and non-extraction groups did not show significant differences from T1 to T2. Therefore, similar relapse may be expected irrespective of treatment plan.

View all citing articles on Scopus

: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported.

View full text

Original articleTreatment outcomes after extraction and nonextraction treatment evaluated with the American Board of Orthodontics objective grading system

Highlights

Introduction

Methods

Results

Conclusions

Section snippets

Material and methods

Results

Discussion

Conclusions

Am J Orthod Dentofacial Orthop

Semin Orthod

Am J Orthod Dentofacial Orthop

Am J Orthod Dentofacial Orthop

Am J Orthod Dentofacial Orthop

Am J Orthod Dentofacial Orthop

Am J Orthod Dentofacial Orthop

Am J Orthod Dentofacial Orthop

Am J Orthod Dentofacial Orthop

Am J Orthod Dentofacial Orthop

Am J Orthod Dentofacial Orthop

Original article
Treatment outcomes after extraction and nonextraction treatment evaluated with the American Board of Orthodontics objective grading system