The Association of Malocclusion Complexity and Orthodontic Treatment Outcomes

Factors influencing treatment outcomes assessed by the American Board of Orthodontics Objective Grading System (ABO-OGS)

BACKGROUND

Treatment outcomes can be influenced by various factors. This study aimed to determine the association between predisposing patient- and treatment-related factors (demographic, cephalometric parameters, skeletal relationships, Discrepancy Index (DI), extractions, treatment type and duration) and treatment outcomes measures according to the American Board of Orthodontics Objective Grading System index (ABO-OGS).

METHODS

Completed cases (N = 100) were included in this cross-sectional study. One calibrated examiner assessed DI, pretreatment lateral cephalometric parameters and ABO-OGS. Patient data, including sex, age, types of malocclusion, extractions, treatment type, and duration, were also collected. Intraexaminer reliability for each measurement was evaluated using the intraclass correlation coefficients. Multiple linear regression analysis, using the backward elimination method with a significance level (α) of 0.05, was used to determine which factors significantly influenced the ABO-OGS score.

RESULTS

From the study, the overall mean ABO-OGS score was 11.36 points. Factors influencing the ABO-OGS score were pretreatment Wits values (p value = .000), L1-NB (°) (p value = .023) and treatment duration (p value = .019). Subjects with lower negative values of Wits and L1-NB (°) tended to have higher ABO-OGS scores. Additionally, the ABO-OGS score tended to be higher for subjects with longer treatment times.

CONCLUSIONS

The majority of treated subjects had satisfactory orthodontic treatment outcomes assessed by the ABO-OGS. The pretreatment severity of skeletal discrepancies determined by the Wits parameter, the degree of retroclined lower incisors and longer treatment duration negatively impacted the treatment outcomes.

Effects of self-ligating brackets and other factors influencing orthodontic treatment outcomes: A prospective cohort study

Objective

The purpose of this study was to evaluate the effects of self-ligating brackets (SBs) and other factors that influence orthodontic treatment outcomes.

Methods

This two-armed cohort study included consecutively treated patients in a private practice. The patients were asked to choose between SBs and conventional brackets (CBs); if any patient did not have a preference, he or she was randomly allocated to the CB or SB group. All patients were treated using an identical archwire sequence. Evaluated parameters were as follows: treatment duration, number of bracket failures, poor oral hygiene, poor elastic wear, extraction, use of orthodontic mini-implants (OMI), OMI failure, American Board of Orthodontics (ABO) Discrepancy Index (DI), arch length discrepancy, and ABO Cast-Radiograph Evaluation (CRE) score. Stepwise regression analysis was performed to generate the equation for prediction of the CRE.

Results

The final sample comprised 134 patients with an average age of 22.73 years. The average DI, CRE, and treatment duration were 21.81, 14.25, and 28.63 months, respectively. Analysis of covariance showed a significant difference in CRE between the CB and SB groups after adjusting for the effects of confounding variables. Stepwise regression analysis using four variables, namely extraction, SB use, poor elastic wear, and additional appliance use, could explain only 25.2% of the variance in the CRE.

Conclusions

Although the CRE was significantly better for CBs than for SBs, the clinical significance of this result seems to be limited. Extraction, SB use, poor elastic wear, and additional appliance use may have significant effects on treatment outcomes.

The Salzmann Index and discrepancy index correlation: Determining a threshold discrepancy index score for Medicaid approval

INTRODUCTION

This study aimed to compare patients' Salzmann Index scores for those who applied for Medicaid orthodontic coverage in Pennsylvania with their corresponding American Board of Orthodontics discrepancy index (DI) scores to assess if there is a correlation between Salzmann and DI scores. In addition, a threshold DI score was calculated that would correspond to Medicaid coverage approval. The study intended to answer the following questions: is there a correlation of 0.7 or greater between a patient's Salzmann Index and their DI? If so, is there a particular DI score that can be used as the minimum score for approving Medicaid orthodontic coverage in the state of Pennsylvania?

METHODS

Salzmann Index scores, DI scores, and approval and disapproval results for Medicaid orthodontic coverage were obtained from 104 subjects aged between 10 and 17 years. A linear regression model was generated to assess if there was a correlation between the Salzmann scores and DI scores. If a correlation coefficient of 0.7 or greater were found, a threshold Salzmann Index score would be determined for subjects who were approved for Medicaid orthodontic coverage. The threshold Salzmann score would be used in the linear regression formula to find the corresponding DI score, which would be designated as the threshold DI score for approval for Medicaid orthodontic coverage in the state of Pennsylvania.

RESULTS

A Pearson correlation of 0.453 was calculated between the 104 Salzmann scores and DI scores, demonstrating a moderate correlation. With the correlation coefficient being lower than 0.7, binary logistic regressions were calculated to assess the predictability between a given Salzmann score and approval and disapproval for Medicaid orthodontic coverage. The Salzmann score had an overall 68.3% success in predicting Medicaid orthodontic coverage approval/disapproval. Of the 58 subjects that were approved for Medicaid orthodontic coverage, 46.6% had Salzmann scores equal to or greater than 25. Of the 46 subjects that were disapproved for Medicaid orthodontic coverage, 78.3% had Salzmann scores equal to or less than 24.

CONCLUSIONS

With the lack of high prediction rates seen from the results of the regression models, the current system of Medicaid does not appear to show consistency for assessing the need for orthodontic treatment coverage. Multiple insurance companies that participate under Medicaid require a Salzmann score of 25 or greater for approval; however, the results show the Salzmann score is arbitrary in terms of approval and disapproval. There appear to be underlying factors apart from the Salzmann score that the Pennsylvania Medicaid system uses to justify whether a patient was approved or denied for coverage.

Occlusal outcome after orthodontic treatment with preadjusted straight-wire and standard edgewise appliances : A retrospective cohort study

PURPOSE

Orthodontic fixed appliances have been proven to be effective in treating a wide variety of malocclusions, and different types of appliances have emerged during recent decades. However, the comparative effects of different appliances have not been adequately assessed. Thus, the aim was to assess the occlusal outcome of orthodontic treatment with preadjusted straight-wire (SWIRE) and standard edgewise (SEDGE) appliances.

METHODS

In all, 56 patients (mean age: 13.5 years; 45% male) receiving extraction-based treatment with either SWIRE or SEDGE appliances were included. Between-group differences in the occlusal outcome assessed with the American Board of Orthodontists Objective Grading System (ABO-OGS) and treatment duration were analyzed statistically at the 5% level.

RESULTS

The average ABO-OGS score was 31.3 ± 7.2 points and 34.0 ± 10.4 points in the SWIRE and SEDGE groups with no statistically significant difference between groups (P = 0.26). Treatment duration was significantly shorter in the SWIRE group compared to the SEDGE group, with an average difference of -6.8 months (95% confidence interval [95% CI] = -9.6 to -4.0 months; P < 0.001). Likewise, fewer visits were needed with SWIRE compared to SEDGE appliances with an average difference of -7.2 visits (95% CI = -10.3 to -4.2 visits; P < 0.001). Adjusting for the influence of any potential confounders did not considerably impact the results.

CONCLUSION

Similar treatment outcomes were observed after premolar extraction treatment with SWIRE and SEDGE appliances. On the other hand, SEDGE appliances were associated with prolonged treatment duration and more visits needed to complete treatment compared to SWIRE appliances.

Impact of post-orthodontic dental occlusion on masticatory performance and chewing efficiency

BACKGROUND

Whether precise orthodontic detailing of occlusion impacts masticatory function is unknown. In this study, we aimed to assess the impact of post-orthodontic dental occlusion on masticatory performance and chewing efficiency.

MATERIALS AND METHODS

Fifty-four adults who completed orthodontic treatment were categorized into two groups using the American Board of Orthodontics (ABO) model grading system: one meeting ABO standards (ABO, N = 29), the other failing to meet them (non-ABO, N = 25). The electromyographic (EMG) signals of the anterior temporalis (AT) and superficial masseter muscles were recorded bilaterally during static (clenching) and dynamic (gum chewing) tests. Chewing efficiency was measured by calculating the median particle size (MPS) and broadness of particle distribution (BPD) after five chewing trials of experimental silicone food at a standardized chewing rate.

RESULTS

Participants of the ABO group had a slightly more symmetric activation of the AT muscles during clenching (P = 0.016) and chewed a gum at a slower rate (P = 0.030). During the standardized chewing test with silicone food, ABO subjects had slightly greater EMG potentials at all muscle locations than non-ABO individuals (all P < 0.05). MPS and BDP did not differ significantly between groups (all P > 0.05).

LIMITATIONS

The severity of the initial malocclusion of the study participants was not in the statistical model as a potential confounder on the outcome measures.

CONCLUSIONS

Meeting ABO standards contributes to a slightly more balanced activation of the temporalis muscles during clenching and more efficient muscle recruitment during chewing but does not improve chewing efficiency.

Outcome assessment of orthodontic clear aligner vs fixed appliance treatment in a teenage population with mild malocclusions

OBJECTIVE

To assess the efficacy and efficiency of treatment in adolescents presenting with mild malocclusions, comparing outcomes using clear aligners to fixed appliances.

MATERIALS AND METHODS

Patients identified retrospectively and consecutively from one private practice had been treated with either clear aligners (Invisalign, Align Technology, Santa Clara, Calif) or fixed appliances (0.022 Damon, Ormco, Orange, Calif; n = 26/group). Assessments of occlusion were made using the American Board of Orthodontics Discrepancy Index (DI) for initial records and Cast-Radiograph Evaluation (CRE) for final records. Number of appointments, number of emergency visits, and overall treatment time were determined from chart reviews. Data were analyzed using Pearson's correlation, Wilcoxon rank tests, unpaired t-tests, and Chi-square tests, with significance set to P ≤ .05.

RESULTS

Pretreatment, the aligner and fixed groups showed no significant difference in overall severity (DI: 11.9 ± 5.3 vs 11.6 ± 4.8) or in any individual DI category. Posttreatment scores showed finishes for the aligner group had fewer discrepancies from ideal relative to the fixed appliance group (CRE: 30.1 ± 8.3 vs 37.0 ± 9.3; P < .01). Patients treated with aligners had fewer appointments (13.7 ± 4.4 vs 19.3 ± 3.6; P < .0001), fewer emergency visits (0.8 ± 1.0 vs 3.6 ± 2.5; P < .0001), and shorter overall treatment time (16.9 ± 5.7 vs 23.4 ± 4.4 months; P < .0001).

CONCLUSIONS

Outcomes for treatment of mild malocclusions in adolescents showed equivalent effectiveness of clear aligners compared to fixed appliances, with significantly improved results for clear aligner treatment in terms of tooth alignment, occlusal relations, and overjet. Assessment of the number of appointments, number of emergency visits, and overall treatment time showed better outcomes for treatment with clear aligners.

Referral patterns of pediatric dentists and general practitioners to orthodontists based on case complexity

OBJECTIVE

The objectives of this research were to investigate and compare general and pediatric dentists' subjective judgments of orthodontic case complexity and to determine how their perceptions of case complexity influence their decisions to refer the patient to an orthodontist.

METHODS

Twenty pediatric dentists and 21 general dentists participated in the study. Pretreatment orthodontic records of 20 patients with a variety of malocclusions and a range of American Board of Orthodontics Discrepancy Index (DI) scores were used. Respondents were asked about their background and training in orthodontics. They were also asked to identify the subjective complexity of each case with the use of a 100-point visual analog scale (VAS) and whether they would refer the patient to an orthodontic specialist. A mixed-model multivariate data analysis was used to evaluate the subjective case complexity with the use of fixed factors such as DI score, type of panel member, experience, annual continuing education rate, and gender. Generalized linear mixed models were used to investigate the referral patterns of the general dentists and pediatric dentists. Level of significance was set at P < 0.05 for all statistical analyses.

RESULTS

General dentists appeared to provide more overall orthodontic treatment than pediatric dentists; many general dentists provide limited orthodontic treatment and clear aligner therapy (P < 0.05). The perceived complexity score for cases was not significantly different between the 2 groups (P = 0.82). The association between DI score and perceived complexity was similar in both groups (P = 0.183) and there was a high correlation between DI and VAS score in the sample (r = 0.71; 95% Cl 0.38-0.87). Pediatric dentists had higher referral rates for cases with DI scores both below and above 20. Significant differences were noted between the pediatric and general dentists in the individual case referral decision as evaluated by the DI (P < 0.037) and VAS (P < 0.042) scores.

CONCLUSIONS

General dentists provided more orthodontic care than the pediatric dentists. Both groups identified case complexity similarly, with only minor differences, but pediatric dentists had higher referral rates to orthodontic specialists regardless of the initial case complexity.

Treatment outcome differences between pass and fail scores and correlation between cephalometric changes and cast-radiograph evaluation of the American Board of Orthodontics

OBJECTIVE:

Using the cast-radiograph evaluation (CRE) score of the American Board of Orthodontics (ABO), the purpose of this study was 1) to find the post-treatment discrepancies that contributed to low-quality outcomes and 2) to identify if there might be any correlation between cephalometric changes and post-treatment discrepancies.

MATERIALS AND METHODS:

About 200 records submitted for the Thai Board of Orthodontics examination were analyzed. Overall, 23 parameters of the CRE scores and 12 cephalometric changes were collected. Based on the total CRE score, the cases were classified into three categories: pass (score <20), undetermined (score 20–30), and fail (score >30). Kruskall–Wallis was used to analyze the differences of mean CRE scores among these three categories. In addition, the cases were further classified into fixed appliance, two-phase and orthognathic surgery groups. Correlation tests were carried out to determine if there might be any association between cephalometric changes and CRE parameters.

RESULTS:

Significant differences of mean CRE scores were found for all CRE components except interproximal contacts. Significant correlation coefficients with the total CRE scores were found for all parameters except interproximal contacts. Significant moderate association was found between lower incisor changes and CRE scores in the two-phase and orthognathic surgery group.

CONCLUSIONS:

In order to improve treatment outcome quality, the top four parameters that orthodontists should pay attention to are occlusal contacts, occlusal relationship, marginal ridges, and alignment and rotations. Cephalometric changes were not suitable as weighting factors for total CRE scores.

Effects of vacuum-formed retainers on periodontal status and their retention efficiency

INTRODUCTION

The stability of treatment results is a major concern in orthodontics. Numerous retention regimens to maintain stability have been introduced. The objectives of this study were to evaluate the effects of vacuum-formed retainers (VFRs) on periodontal tissues and the retention efficiency of VFRs.

METHODS

Forty patients were included in this study. Clinical effectiveness of VFRs for nighttime use only over a 12-month period was assessed by using the American Board of Orthodontics' Objective Grading System. Periodontal measurements and indexes were recorded and evaluated immediately after removal of the braces and after 1, 6, and 12 months of VFR use.

RESULTS

There was no significant change in the total Objective Grading System score between the end of the active treatment period and the end of the 12-month retention period. However, regarding periodontal measurements, the plaque and gingival indexes decreased, whereas the bleeding on probing, probing depth, calculus index, and clinical attachment loss increased between the evaluated periods.

CONCLUSIONS

In terms of periodontal health, the use of VFRs resulted in a slight periodontal attachment loss that seemed to be clinically insignificant, without gingival inflammation or recession. In terms of stability, VFRs were found to be effective in orthodontic retention.

[Clinical and diagnostic rationale for the final stage of orthodontic treatment]

The aim of the study was to improve the efficiency of the final stage of orthodontic treatment. The study included 32 patients divided into two groups of 16. Orthodontic treatment was performed using a bracket system active self-ligation straight arc technique with step adjustment anthropometric quantitative evaluation system (The ABO Model Grading System). Centric occlusion and centric relation were analyzed at baseline and after treatment by mandible position indicator MPI (Mandibular Position Indicator). The first group received treatment according to conventional protocol, in the second group braces were readjusted by indirect bonding after ABO anthropometric measurements. The efficiency of orthodontic treatment using ABO system at the late stages of adjustment in the second group was significantly higher than in the first group (p=0.002248; p=0.023431, respectively). MPI analysis in the first group in 10 (62.5%) patients showed mismatch of centric occlusion and centric relation not seen in the second group. In 3 (18.75%) patients of group 2 the difference did not exceed 0.5 mm which was considered normal. Thus, the application of ABO anthropometric system followed by readjustment of incorrectly positioned brackets by indirect bonding promotes MPI values improvement, which in turn allows getting the most accurate, and stable results of orthodontic treatment.

Outcome assessment of lingual and labial appliances compared with cephalometric analysis, peer assessment rating, and objective grading system in Angle Class II extraction cases

OBJECTIVE

To validate our hypothesis that there would be significant differences in treatment outcomes, including cephalometric values, degree of root resorption, occlusal indices, and functional aspect, between cases treated with labial and lingual appliances.

MATERIALS AND METHODS

Twenty-four consecutively treated Class II cases with extractions and lingual appliance were compared with 25 matched cases treated with extraction and labial appliance. Orthodontic treatment outcomes were evaluated by cephalometric analysis, peer assessment rating, and an objective grading system (OGS). Additionally, functional analysis was also performed in both groups after orthodontic treatment. Statistical comparison was performed using the Wilcoxon signed rank test within the groups, and the Mann-Whitney U-test was used to compare between the labial and lingual groups.

RESULTS

The only significant difference between the groups was that the interincisal angle was larger in the lingual group than in the labial group. OGS evaluation showed that control over root angulation was significantly worse in the lingual group than in the labial group. There was no significant difference between groups in the amount of root resorption or in functional evaluation.

CONCLUSIONS

Generally, lingual appliances offer comparable treatment results to those obtained with labial appliances. However, care should be taken with lingual appliances because they are more prone to produce uprighted incisors and root angulation.

Relationship between pretreatment case complexity and orthodontic clinical outcomes determined by the American Board of Orthodontics criteria

OBJECTIVE

To evaluate the relationship between pretreatment case complexity and orthodontic treatment outcomes.

MATERIALS AND METHODS

The total sample contained 1693 cases (853 females and 840 males, mean age  =  16.3 years) from the archives of postgraduate orthodontic clinics. The complexity of each case was evaluated using the American Board of Orthodontics (ABO) Discrepancy Index (DI), and orthodontic clinical outcomes were evaluated using the ABO Objective Grading System (OGS). Only one investigator evaluated all cases. Multivariate analysis of variance, correlation analysis, and multiple variable regression analysis were used for statistical evaluation (P < .05 as significant).

RESULTS

The mean total DI score was 16.2, and the mean total OGS score was 18. No significant correlation was found between the total DI and the total OGS scores. However, pretreatment overbite, lateral open bite, crowding, buccal posterior crossbite, and other components affected the total OGS score significantly. The highest percentage of passing OGS values was found for cases of medium-level complexity.

CONCLUSION

This retrospective study of university clinical records showed that the posttreatment clinical outcomes were significantly affected from pretreatment case complexity. Posttreatment alignment was affected significantly from pretreatment buccal posterior crossbite and cephalometric values. Similarly, posttreatment buccolingual inclination was affected from pretreatment anterior open bite, occlusion, and other factors. Occlusal contacts were affected significantly from pretreatment lingual posterior crossbite and other factors. In addition, we determined that posttreatment root angulations were affected significantly from pretreatment crowding values.