2023-2024 American Board of Orthodontics practice analysis study: Part 1.

As a specialty board, the American Board of Orthodontics (ABO) serves to protect the public and the orthodontic specialty by certifying orthodontists. The demonstration of commitment to lifelong learning and self-improvement is critical to achieving the highest level of patient care. The ABO completed a practice analysis study in 2023 to ensure all examinations represent current assessments of proficiency in orthodontics at a level of quality that satisfies professional expectations. The practice analysis is essential to providing a demonstrable relationship between the examination content and orthodontic practice and provides a critical foundation for ABO's examination programs.

Assessment of Streptococcus mutans biofilms on orthodontic adhesives over 7 days.

INTRODUCTION: The purpose of this study was to compare the metabolism of Streptococcus mutans biofilms after 1-7 days of growth on different orthodontic adhesives. METHODS: Specimens of 6 commercial orthodontic adhesives were fabricated in custom-made molds and polymerized using a light-emitting diode light-curing unit. Bioluminescent S mutans (UA159:JM10) biofilms were grown on ultraviolet-sterilized specimens for 1, 3, 5, and 7 days (n = 18 biofilms/d/product) in anaerobic conditions at 37°C. The metabolism of biofilms (relative luminescence unit [RLU]) was measured 0, 2, 4, and 6 minutes after exposure to D-luciferin solution using a microplate reader. A linear mixed-effects model was used to analyze the logarithm of RLU (log RLU). The model included fixed effects of products, days, and minutes. Tukey-Kramer post-hoc tests were then performed on the significant predictors of log RLU (α = 0.05). RESULTS: Days (P <0.0001) and minutes (P <0.0001) were independent predictors of log RLU, but the products were not (P = 0.5869). After adjusting for minutes, the log RLU was analyzed with a post-hoc test, and all differences between days were significant with the exceptions of day 3 from day 5 (P = 0.0731) and day 5 from day 7 (P = 0.8802). After adjusting for day, log RLU was analyzed with a post-hoc test and all differences in minutes were significant. CONCLUSIONS: No significant differences in the metabolism of S mutans biofilms were observed among the 6 orthodontic adhesives. Biofilms that were grown for 3 days demonstrated the highest levels of biofilm metabolism as evidenced by higher mean log RLU values relative to 1, 5, and 7-day growth durations.

Pairing orthodontic adhesive resins and light-curing units for optimal degree of conversion.

OBJECTIVES: The purpose of this study was to identify the combination of orthodontic adhesive resins and light-emitting diode (LED) light-curing units (LCUs) that result in the highest degree of resin conversion (DC). The hypothesis tested was that pairing orthodontic resins with LCUs from the same manufacturer produces higher DC versus unpaired resins and LCUs. METHODS: Pre-polymerization spectra of adhesive resins (Transbond XT [3M Unitek], BracePaste [American Orthodontics] or Opal Bond MV [Opal by Ultradent]) were obtained at oral temperature (37°C) using an attenuated total reflectance (ATR) diamond crystal (Golden Gate, Specac) in a Fourier-transform infrared (FTIR) spectrometer (Nicolet IS50). Resin specimens were polymerized using various LCUs (Ortholux Luminous [3M Unitek], Blue Ray 3 [American Orthodontics], or VALO Ortho Cordless [Ultradent Products, Inc.]) before obtaining post-polymerization infrared (IR); spectra. Twelve LCU-resin combinations were tested (n = 20/combination), half with a bracket present (Mini Diamond Twin, Ormco) and half without. DC values (%) were calculated using the two-frequency method and tangent-baseline technique. Data for each resin were statistically analyzed using General Linear Models and Student-Newman-Keuls post hoc tests (α = 0.05). RESULTS: Statistically significant differences were found within each resin for the groups without brackets present (P < 0.0001), the groups with brackets present (P < 0.0001), and the groups with brackets when compared with the manufacturer-paired group without a bracket (P < 0.0001). CONCLUSIONS: Adhesive resins and LCUs from the same manufacturer did not consistently result in statistically higher mean DC values than unpaired combinations. Metal brackets do not uniformly reduce the degree of conversion of adhesive resins when assessed using IR spectrometry.

Accuracy of digital light processing printing of 3-dimensional dental models.

INTRODUCTION: This study aimed to investigate whether a digital light processing (DLP) printer could perform efficiently and with adequate accuracy for clinical applications when used with different settings and variations in the orientation of models on the build plate. METHODS: Digital impressions of the oral environment were collected from 15 patients. Subsequently, digital impressions were used to make 3-dimensional printed models using the DLP printing technique. Three variables of the printing technique were tested: placement on the build plate (middle vs corner), thickness in the z-axis (50 microns vs 100 microns), and hollow vs solid shell. After being printed with different printing techniques and orientations on the same printer, a total of 240 maxillary and mandibular arches were measured. These variables generated 8 printing combinations. Tooth and arch measurements on each model type were compared with each other. Intraobserver reliability of the repeated measurement error was assessed using intraclass correlation coefficient. RESULTS: All mean differences among the printing variations were statistically insignificant. The Bland-Altman plots verified a high degree of agreement among all model sets and printing variations. In addition, the measurements were highly reproducible; this was demonstrated by the high intraclass correlation coefficient for all measurements recorded. CONCLUSIONS: The DLP printer produced clinically acceptable models in all areas of the build plate, with hollow and solid model shells, and at its high-speed setting of 100 microns. The applications of the DLP printer tested should be a viable option for printing in a clinical environment at a high-speed setting while filling the build plate and printing with less resin.

Trends in Medicaid-funded adolescent comprehensive orthodontic treatment provided by orthodontists to children in Oklahoma between 2010 and 2016.

INTRODUCTION: The aim of this study was to evaluate the trends and rates of Medicaid-funded orthodontic treatment provided by orthodontists to children younger than 18 years in Oklahoma. METHODS: Enrollment and claims data were evaluated from the Oklahoma Medicaid program for a 7-year period, January 2010 through December 2016. Medicaid total enrollment data by age, sex, race or ethnicity, and county were included. Claims data were collected both for any dental services and comprehensive orthodontic treatment for adolescents. Descriptive statistics were used for the study variables. Proportions and odds ratios were calculated and compared using a chi-square test. RESULTS: Children aged between 15 and 18 years received orthodontic treatment more frequently than children aged between 6 and 14 years. Females received orthodontic treatment more frequently than males. Caucasians received orthodontic treatment more frequently than other races. Children who live in rural areas received orthodontic treatment more frequently than those living in urban areas. CONCLUSIONS: Comprehensive orthodontic patients are more likely to be Caucasian females between the ages of 15 and 18 years living in rural areas. The Hispanic community is growing significantly in the Medicaid population. Access to care is still a problem faced by many.

Flexural properties of rectangular nickel-titanium orthodontic wires when used as ribbon archwires.

OBJECTIVE: To compare the flexural properties of rectangular nickel-titanium (Ni-Ti) orthodontic wires in occlusoapical and faciolingual orientations using a standardized test method. MATERIALS AND METHODS: Twenty-two rectangular Ni-Ti wire groups were tested in occlusoapical (ribbon) orientation: eight conventional Ni-Ti products, five superelastic Ni-Ti products, and nine thermal Ni-Ti products (n = 10 per group). Six products of thermal Ni-Ti wire were tested in faciolingual (edgewise) orientation. A three-point bending test was performed to measure deactivation force at 3.0-, 2.0-, 1.0-, and 0.5-mm deflections of each rectangular wire at 37.0 ± 0.5°C. Analysis of variance and post hoc Student-Newman-Keuls tests were used to compare the mean values of the different groups (α = .05). RESULTS: The ranges of deactivation forces varied greatly with different kinds, sizes, products, and deflections of Ni-Ti wires. One product of conventional and superelastic Ni-Ti wires had steeper force-deflection curves. Four products had similarly shaped flat force-deflection curves, whereas the sixth product had a moderately steep force-deflection curve. Thermal Ni-Ti wires had smaller deactivation forces ranging from 0.773 N (78.8 g) to 2.475 N (252.4 g) between deflections of 1.0 and 0.5 mm, whereas wider ranges of force from 3.371 N (343.7 g) to 9.343 N (952.7 g) were predominantly found among conventional Ni-Ti wires between deflections of 3.0 and 2.0 mm. CONCLUSIONS: Clinicians should critically select archwires for use in the occlusoapical orientation not only based on Ni-Ti wire type, size (0.022 × 0.016-in or 0.025 × 0.017-in), and product but also with deactivation deflections from 0.5 and 1.0 mm to obtain light forces in the occlusoapical orientation.

Accuracy of 3-dimensional printed dental models reconstructed from digital intraoral impressions.

INTRODUCTION: A rapidly advancing digital technology in orthodontics is 3-dimensional (3D) modeling and printing, prompting a transition from a more traditional clinical workflow toward an almost exclusively digital format. There is limited literature on the accuracy of the 3D printed dental models. The aim of this study was to assess the accuracy of 2 types of 3D printing techniques. METHODS: Digital and alginate impressions of the oral environment were collected from 30 patients. Subsequently, digital impressions were used to print 3D models using digital light processing (DLP) and polyjet printing techniques, and alginate impressions were poured up in stone. Measurements for the 3 model types (digital, DLP, and polyjet) were compared with the stone models. Tooth measurements (first molar to first molar) included mesiodistal (crown width) and incisal/occlusal-gingival (crown height). Arch measurements included arch depth and intercanine and intermolar widths. Intraobserver reliability of the repeated measurement error was assessed using intraclass correlation coefficients. RESULTS: The intraclass correlation coefficients were high for all recorded measurements, indicating that all measurements on all model types were highly reproducible. There were high degrees of agreement between all sets of models and all measurements, with the exception of the crown height measurements between the stone and DLP models, where the mean difference was statistically significant. CONCLUSIONS: Both the DLP and polyjet printers produced clinically acceptable models and should be considered viable options for clinical application.

Volumetric Cleft Changes in Treatment With Bone Morphogenic Protein/ß-Tricalcium Phosphate Versus Grafts From the Iliac Crest or Symphysis.

PURPOSE: To compare the volumetric changes in successfully treated clefts with secondary alveolar grafting using recombinant human bone morphogenic protein-2 (rhBMP-2) delivered in ß-tricalcium phosphate (ßTCP) scaffold versus autogenous grafts obtained from the iliac crest and mandibular symphysis. PATIENTS AND METHODS: We performed a retrospective cohort study of cone-beam computed tomography scans of 25 subjects with unilateral or bilateral clefts. Of the 25 patients, 7 received an iliac crest bone graft, 9 received a mandibular symphyseal bone graft, and 9 subjects received the rhBMP-2/ßTCP bone substitute. Volumetric rendering software was used to calculate the amount of new bone formation and residual bone defect present in the cleft area. The data were analyzed using Wilcoxon and Kruskal-Wallis tests and Pearson's correlation coefficient. RESULTS: The mean percentage of new bone formation for the iliac crest, symphysis, and rhBMP-2/ßTCP was 85.47, 80.56, and 81.22%, respectively (P = .0854). The initial cleft volume had a weak positive correlation with the percentage of new bone formation (r = 0.18), but the postoperative residual cleft volume had a strong negative correlation (r = 0.71). CONCLUSIONS: rhBMP2 delivered in a ßTCP scaffold in alveolar cleft patients can be a viable alternative to autogenous iliac crest and symphysis grafts, eliminating donor site morbidity.

Postsurgical volumetric airway changes in 2-jaw orthognathic surgery patients.

INTRODUCTION: Findings from early cephalometric studies on airway changes after 2-jaw orthognathic surgery have been challenged because the previous anteroposterior interpretation of airway changes can now be evaluated in 3 dimensions. The aims of this study were to use cone-beam computed tomography to quantify the nasopharynx, oropharynx, and total airway volume changes associated with skeletal movements of the maxilla and mandible in a sample of patients undergoing 2-jaw orthognathic surgery for correction of skeletal malocclusion. METHODS: Skeletal movements and airway volumes of 71 postpubertal patients (31 male, 40 female; mean age, 18.8 years) were measured. They were divided into 2 groups based on ANB angle, overjet, and occlusion (Class II: ANB, >2°; overjet, >1 mm; total, 35 subjects; and Class III: ANB, <1°; overjet, <1 mm; total, 36 subjects). Presurgical and postsurgical measurements were collected for horizontal, vertical, and transverse movements of the maxilla and the mandible, along with changes in the nasopharynx, oropharynx, and total airways. Associations between the directional movements of skeletal structures and the regional changes in airway volume were quantified. Changes in the most constricted area were also noted. RESULTS: Horizontal movements of D-point were significantly associated with increases in both total airway (403.6 ± 138.6 mm(3); P <0.01) and oropharynx (383.9 ± 127.9 mm(3); P <0.01) volumes. Vertical movements of the posterior nasal spine were significantly associated with decreases in total airway volume (-459.2 ± 219.9 mm(3); P = 0.04) and oropharynx volume (-639.7 ± 195.3 mm(3); P <0.01), increases in nasopharynx (187.2 ± 47.1 mm(3); P <0.01) volume, and decreases in the most constricted area (-10.63 ± 3.69 mm(2); P <0.01). In the Class III patients only, the vertical movement of D-point was significantly associated with decreases in both total airway (-724.0 ± 284.4 mm(3); P = 0.02) and oropharynx (-648.2 ± 270.4 mm(3); P = 0.02) volumes. A similar negative association was observed for the most constricted area for the vertical movement of D-point (-15.45 ± 4.91 mm(2); P <0.01). CONCLUSIONS: Optimal control of airway volume is through management of the mandible in the horizontal direction and the vertical movement of the posterior maxilla for all patients. The surgeon and the orthodontist should optimally plan these movements to control gains or losses in airway volume as a result of orthognathic surgery.

Digital tooth-based superimposition method for assessment of alveolar bone levels on cone-beam computed tomography images.

INTRODUCTION: Cone-beam computed tomography images have been previously used for evaluation of alveolar bone levels around teeth before, during, and after orthodontic treatment. Protocols described in the literature have been vague, have used unstable landmarks, or have required several software programs, file conversions, or hand tracings, among other factors that could compromise the precision of the measurements. The purposes of this article are to describe a totally digital tooth-based superimposition method for the quantitative assessment of alveolar bone levels and to evaluate its reliability. METHODS: Ultra cone-beam computed tomography images (0.1-mm reconstruction) from 10 subjects were obtained from the data pool of the University of Oklahoma; 80 premolars were measured twice by the same examiner and a third time by a second examiner to determine alveolar bone heights and thicknesses before and more than 6 months after orthodontic treatment using OsiriX (version 3.5.1; Pixeo, Geneva, Switzerland). Intraexaminer and interexaminer reliabilities were evaluated, and Dahlberg's formula was used to calculate the error of the measurements. RESULTS: Cross-sectional and longitudinal evaluations of alveolar bone levels were possible using a digital tooth-based superimposition method. The mean differences for buccal alveolar crest heights and thicknesses were below 0.10 mm for the same examiner and below 0.17 mm for all examiners. The ranges of errors for any measurement were between 0.02 and 0.23 mm for intraexaminer errors, and between 0.06 and 0.29 mm for interexaminer errors. CONCLUSIONS: This protocol can be used for cross-sectional or longitudinal assessment of alveolar bone levels with low interexaminer and intraexaminer errors, and it eliminates the use of less reliable or less stable landmarks and the need for multiple software programs and image printouts. Standardization of the methods for bone assessment in orthodontics is necessary; this method could be the answer to this need.

Evaluation of 3 retention protocols using the American Board of Orthodontics cast and radiograph evaluation.

INTRODUCTION: The purpose of this study was to quantify tooth movement among different retention protocols after the orthodontic appliances were removed. METHODS: A total of 90 patients were evaluated using the American Board of Orthodontics discrepancy index and the cast and radiograph evaluation at debond and the 1-year recall. These patients were equally divided into 3 retention protocols: upper Hawley/lower Hawley, upper Hawley/lower bonded, and upper Essix/lower bonded. The patients were then equally grouped by extraction or nonextraction treatment and case complexity. Paired t tests were used to compare the paired sample means. Analysis of variance tests were used to compare the means for more than 2 groups. A 2-sided 0.05 alpha level was used to define statistical significance. RESULTS: The upper Hawley/lower bonded showed the greatest amount of settling, and the upper Essix/lower bonded had the least settling, but these differences were statistically insignificant. The differences between the extraction and nonextraction treatments were not significant. The group with low discrepancy index scores showed significantly more settling than did the group with high discrepancy index scores. CONCLUSIONS: The cast and radiograph evaluation variables that improved overall were marginal ridges, overjet, occlusal contacts, interproximal contacts, root angulation, and total cast and radiograph score. The cast and radiograph evaluation variables that worsened were alignment/rotation, buccolingual inclination, and occlusal relationship. Extraction or nonextraction treatment led to no real difference in settling. The discrepancy index, or initial case complexity, was the greatest factor in determining the improvement of occlusion or settling during the retention phase.

Treatment time: SureSmile vs conventional.

AIM: To understand the efficiency of SureSmile treatment vs conventional treatment. METHODS: First, 12,335 completed patient histories representing different treatment philosophies and geographically diverse practices were collected. Included were 9,390 SureSmile patients and 2,945 conventional patients. Variables in these patient records included: (1) treatment time, months from bonding to debonding; (2) malocclusion class, Angle Class I, II, or III; (3) patient age, adolescents (< 18 years) or adults (≥ 18 years); and (4) patient visits, total number of treatment visits. Nonparametric regression tests were used to analyze the data. RESULTS: The median treatment time for the SureSmile patient pool (15 months) was 8 months shorter than that of the conventional patient pool (23 months). The median care cycle length of Class II SureSmile patients (13 months) was 2 months shorter than that of Class I SureSmile patients (15 months) and 3 months shorter than that of Class III SureSmile patients (16 months). SureSmile patients (14 visits) had four fewer median treatment visits than conventional patients (18 visits). All results were significant at P = .001. No significant differences were noted between the median care cycle lengths of adolescents and adults. CONCLUSION: This study found that SureSmile treatment facilitates more timely care than conventional treatment. Further prospective studies are required to elucidate the effectiveness of SureSmile treatment.

A CBCT comparison of anterior root resorption in SureSmile and conventional edgewise treatments.

AIM: To utilize cone beam computed tomography (CBCT) to analyze the amount of linear root resorption that occurs in maxillary and mandibular permanent incisors during orthodontic treatment when comparing the SureSmile technique with conventional edgewise treatment. In addition, patient and treatment factors that may be correlated with root resorption were studied. METHODS: The records of 28 patients (14 SureSmile and 14 edgewise) treated in an orthodontic office were used for this study. CBCTs were taken of all patients prior to (T1) and after completion of orthodontic treatment (T2). Total tooth length of the permanent incisors were measured on the CBCTs at T1 and T2. Root resorption was calculated for each tooth by subtracting T1 from T2. RESULTS: No statistically significant differences in mean root resorption (MRR) were found for the permanent incisors when comparing SureSmile patients with conventional edgewise patients. The MRR for each tooth was found to be less than 1 mm when using either treatment modality. Subjects with increased resorption included Class II malocclusion, severe overjet, and treatment time greater than or equal to 25 months. Sex and the use of Class II elastics showed no significant differences in mean root resorption. CONCLUSION: No differences were found in root resorption of the permanent incisors when comparing SureSmile and edgewise treatments.

Prostaglandin E2 levels in gingival crevicular fluid during tooth- and bone-borne expansion.

The purpose of this study was to compare Prostaglandin E(2) (PGE(2)) levels in gingival crevicular fluid (GCF) of young adults with maxillary constriction during tooth- and bone-borne expansion. Thirty patients, 15 females and 15 males, with a mean age of 17.3 +/- 2.8 years were divided into three groups. Group I consisted of 10 patients, five females and five males, treated by transpalatal distraction (TPD) as a bone-borne device, group II 10 patients, five females and five males, with a Hyrax appliance as a tooth-borne device, and a control group of 10 patients, five females and five males, without any expansion appliances. GCF samples were collected with filter paper strips at six observation periods in order to evaluate the effect of heavy orthopaedic forces in both groups. In group II, the samples were additionally collected at two pre-treatment time points in order to evaluate the effect of the forces generated by the separators. An automated enzyme immunoassay was used to measure PGE(2) in the GCF. The differences within the groups were evaluated with a pairwise t-test and the differences between the groups were determined by the Mann-Whitney U-test. The mean PGE(2) level was significantly elevated on day 4 after placement of the separators in group II (P < 0.05). The PGE(2) values in group II were significantly different to those in group I and the controls at all observation periods. Lower PGE(2) levels were observed in group I compared with group II and the controls. Expansion using the TPD method could potentially enhance the prognosis of the teeth by inducing more skeletal dental changes when compared with the Hyrax appliance.

Contact damage to root surfaces of premolars touching miniscrews during orthodontic treatment.

INTRODUCTION: Our aim in this clinical study was to examine premolar root surfaces after intentional contact with miniscrews. METHODS: Ten patients (5 male, 5 female; mean age, 15.8 years; range, 13.5-23.2 years) with 2 maxillary first premolars to be extracted as part of their orthodontic treatment participated in the study. Two miniscrews were placed in each patient, and the first premolar roots were tipped into contact with the miniscrews by using tipping springs with a standardized force. Half of the experimental teeth were kept in contact with the screws for 4 weeks (mild resorption) and the other half for 8 weeks (severe resorption). In 5 patients, the screws were removed, and, in the remaining 5, the springs were removed to allow the roots to move back. The roots were allowed to recover for 4 or 8 weeks before extraction. Two premolars with accidental direct contact were used as controls. All teeth were prepared, coated, and examined with scanning electron microscopy. RESULTS: In the control group, the periodontal ligament was removed and the dentin surface denuded. The experimental groups showed signs of resorption with structural surface irregularities. However, no apparent denuded dentin surfaces were seen. Although some resorption lacunae were still discernible at 8 weeks, the collagen fibers fully covered the affected areas. The immature fiber organization in the deepest crater represented the ongoing process of fiber reorganization, compared with the fully matured surface areas surrounding the crater. CONCLUSIONS: The results indicate that root surfaces that touch miniscrews show swift repair and almost complete healing within a few weeks after removal of the screw or the orthodontic force. These findings are based on 10 patients only; verification in a larger study sample is needed.