Buccolingual Inclination Research Articles

Buccolingual Inclination of Canine and First and Second Molar Teeth and the Curve of Wilson in Different Sagittal Skeletal Patterns of Adults Using Cone-Beam Computed Tomography.

Objectives This study aimed to assess the buccolingual inclination of canine and first and second molar teeth and the curve of Wilson in different sagittal skeletal patterns in untreated adults using cone-beam computed tomography (CBCT). Materials and Methods Sixty-six CBCT scans of adults (mean age: 28.74 ± 5.25 years) were evaluated in this cross-sectional study. The images were standardized using the Frankfurt horizontal plane and the interorbital line. The sagittal skeletal pattern was determined using the ANB angle and Wits appraisal. Inclination angles were measured by NNT Viewer and Mimics software. The curve of Wilson was measured by connecting the tips of mesiobuccal and mesiolingual cusps of maxillary first and second molars along the buccal groove and measuring the formed angle. Data were analyzed using ANOVA. Results The intraobserver agreement was 0.969. The mean inclination of maxillary first and second molars in class I and III patients was significantly higher than that in class II patients (P < 0.05). The mean inclination of mandibular first and second molars in class II patients was significantly higher than that in class I and III patients (P < 0.05). The difference in inclination of maxillary and mandibular canine teeth was not significant (P > 0.05). The mean curve of Wilson in second molars of class II patients was significantly higher than that in class I patients (P < 0.05). Conclusion In different sagittal skeletal patterns, a compensatory relationship exists between the opposing teeth, which, along with the standards of crowns, can be used to determine the appropriate position of teeth in dental arch.

Can we estimate root axis using a 3-dimensional tooth model via lingual-surface intraoral scanning?

This research aimed to compare the estimation error of the root axis using 3-dimensional (3D) tooth models at the midtreatment stage between the whole-surface scan (WSS) and lingual-surface scan (LSS) methods. The sampleconsisted of 208 teeth (26 each of central incisors, canines, second premolars, and first molars in the maxillary and mandibular dentition) from 13 patients whose pre- and midtreatment intraoral scan and cone-beam computed tomography (CBCT) were available. The 3D tooth models were constructed by merging the intraoral-scan crowns and the CBCT-scan roots obtained at the pretreatment stage. To estimate the root axis at the midtreatment stage, we superimposed the individual 3D tooth models onto the midtreatment intraoral scan obtained by the WSS and LSS methods. The midtreatment CBCT scan was used as the gold standard to determine the real root axis. The estimated root axis in terms of mesiodistal angulation and buccolingual inclination was measured in the WSS and LSS methods, and statistical analysis was performed. The estimation errors of the mesiodistal angulation and buccolingual inclination were<2.0° in both methods. The LSS method demonstrated a statistically larger but clinically insignificant estimation error than the WSS method in the mandibular canine (mesiodistal angulation, 1.95° vs 1.62°) and the total tested teeth (mesiodistal angulation, 1.40° vs 1.29°; buccolingual inclination, 1.51° vs 1.41°). Because the estimation errors of the root axis angle using the 3D tooth model by the WSS and LSS methods were within the clinically acceptable range, the root axis can be estimated by both methods.

A prospective cohort study on the effects of RME in the mandibular dentition of cleft subjects

PurposeRapid maxillary expansion (RME) is the most frequent orthopedic procedure in cleft subjects. However, little is known about its effects on the mandible. The aim of this study was to investigate the spontaneous response of the mandibular teeth following RME. MethodsThis prospective cohort study was carried out with a sample of thirty participants with unilateral cleft lip and palate (UCLP), 8–15 years old, who had transverse maxillary deficiency. Two participants were excluded. They were allocated into three groups: G1 (n = 10), G2 (n = 10), and G3 (n = 8). G1 was treated with a Fan-type expander; G2 with an iMini expander; and G3 with a Hyrax expander. Measurements were performed in Cone Beam CT scans obtained before treatment (T1) and 3 months post-expansion (T2). The primary outcomes were buccolingual inclination of mandibular first molars and canines, and intercanine and intermolar width at different levels. ResultsDental changes were significant (P < 0.05) for intercanine width, increasing in G1 and G2, and for intermolar width, increasing in G2 and G3. There were no significant differences among groups (P > 0.05). ConclusionRME in UCLP subjects performed with these expanders may lead to significant spontaneous changes in both anterior and posterior region of the mandible.

The Herbst appliance combined with a completely customized lingual appliance: A retrospective cohort study of clinical outcomes using the American Board of Orthodontics Objective Grading System

In this retrospective study we aimed to evaluate the quality of treatment outcomes using the American Board of Orthodontics (ABO) scoring system with a completely customized lingual appliance used in combination with a Herbst appliance for Class II correction. Patient selection criteria for this study were Class II division 1, II/2 or subdivision treated with a WIN® lingual appliance combined with an L-pin Herbst device. Thirty-two consecutively debonded cases were included in this retrospective case series. Pre- and post- treatment dental casts, dental set-ups, panoramic X-rays, cephalometric analysis, photographs and clinical files were available for data collection. The primary outcome was the ABO score based on the Discrepancy Index (ABO DI) including: overjet, overbite, anterior open bite, lateral open bite, crowding, occlusion (Angle class), lingual posterior crossbite, buccal posterior crossbite, ANB, IMPA and SN-GoGN angles and the Cast-Radiograph Evaluation (ABO CR-Eval) comprising of alignment/rotations, marginal ridges, buccolingual inclination, overjet, occlusal contacts, occlusal relationship (Angle class), interproximal contacts and root angulation. In addition, overjet, overbite and Class II correction were also evaluated on pre- and post-treatment models. The secondary outcome was bracket failure and complications related to the Herbst device. The study cohort included 18 female and 12 male patients with a mean age of 15.8 (range 12, 6- 18, 5). Twenty patients were Class II division 1 and ten were Class II division 2. The mean pre-treatment value of ABO DI was 20.8 (range 10-39); more than two-thirds of the sample were rated as being either of moderate difficulty (ABO DI: 16-24) or severe (ABO DI: over 25). The average post-treatment ABO Cast-Radiograph Evaluation score was 15.0 (SD=4.4), which is considered a passing score. Twenty-six patients had a score equal or lower than 20 (undisputed passing score). The Class II discrepancy was effectively corrected from a score of 16.83 penalty points (SD: 3.65) pre-treatment to a score of 1.57 (SD: 1.70) post-treatment. No association was found between initial and final Class II occlusal relationships (P=0.42), indicating that regardless of the initial discrepancy, no difference in the success of Class II correction was observed. The mean bracket failure rate was 3.8 per patient. Herbst related complications were few: 1.6 per patient, with the majority of complications being of little consequence and with 43% of the patients having no breakages. The completely customized lingual appliance assessed in this study combined with an L-pin Herbst led to effective Class II correction regardless of the initial severity of the sagittal discrepancy. The average ABO CR-Eval score for this sample was well below the undisputed passing score indicating a high quality of treatment outcomes.

Treatment Efficacy of Invisalign: Literature Review Update

Purpose: Inconsistency between computer prediction and actual tooth movement in Invisalign treatment always limits clinical judgment. The objective of this review was to update the evidence on the treatment efficacy of the Invisalign appliance. Material and Methods: Medical databases were screened for relevant peer-reviewed articles from 2000 to 2018 for the use of Invisalign as a treatment intervention. All human studies other than case reports and case series were included. Results: A total of 25 articles (4 RCTs, 6 prospective cohort studies, 15 retrospective cohort studies) were included. Treatment outcomes have been improving over the past 17 years. Invisalign treatment achieved results comparable with those of fixed appliances in extraction cases, except for buccolingual inclination (p<0.005) and occlusal contacts (p<0.001). For specific tooth movement, the highest accuracy was for arch expansion (upper: 72.8%, lower: 87.7%) and molar distalization (87%). Rotation of rounded tooth and overbite control with aligners was unpredictable. Conclusions: Invisalign treatment for controlling buccolingual inclination and occlusal contacts were less than ideal. None of the tooth movement was completely in line with predictions. Auxiliary or revised prescription may be needed to achieve high-quality results. Because the material, treatment design, and evaluation methods differ among studies, results should be interpreted carefully.

Construction reproducibility of a composite tooth model composed of an intraoral-scanned crown and a cone-beam computed tomography-scanned root.

ObjectiveTo evaluate the construction reproducibility of a composite tooth model (CTM) composed of an intraoral-scanned crown and a cone-beam computed tomography (CBCT)-scanned root.MethodsThe study assessed 240 teeth (30 central incisors, 30 canines, 30 second premolars, and 30 first molars in the maxillary and mandibular arches) from 15 young adult patients whose pre-treatment intraoral scan and CBCT were available. Examiner-Reference (3 years’ experience in CTM construction) and Examiners-A and Examiner-B (no experience) constructed the individual CTMs independently by performing the following steps: image acquisition and processing into a three-dimensional model, integration of intraoral-scanned crowns and CBCT-scanned teeth, and replacement of the CBCT-scanned crown with the intraoral-scanned crown. The tooth axis angle in terms of mesiodistal angulation and buccolingual inclination of the CTMs constructed by the three examiners were measured. To assess the construction reproducibility of CTMs, intraclass correlation coefficient (ICC) assessments were performed.ResultsThe ICC values of mesiodistal angulation and buccolingual inclination among the 3 examiners showed excellent agreement (0.950–0.992 and 0.965–0.993; 0.976–0.994 and 0.973–0.995 in the maxillary and mandibular arches, respectively).ConclusionsThe CTM showed excellent construction reproducibility in mesiodistal angulation and buccolingual inclination regardless of the construction skill and experience levels of the examiners.

Can palatal depth influence the buccolingual inclination of molars? A cone beam computed tomography-based retrospective evaluation.

To interpret a correlation between buccolingual inclination of molars and palatal depth in hyperdivergent patients and to identify importance of determining inclination of molars in assessing transverse discrepancies (as skeletal or dental). This was a retrospective cone beam computed tomography (CBCT) study. The study was conducted in the Department of Orthodontics, Saveetha Dental College and Hospital, Tamil Nadu, India. This was a retrospective CBCT study of 79 patients who underwent diagnostic CBCT for treatment purposes. The CBCT scans were evaluated systematically and the required parameters were accessed with suitable reference planes. Student's t-test (95% confidence interval) was performed to determine buccolingual inclination of first molars between the right and left sides. Only patients with a vertical growth pattern and skeletal class I relation were included and they were classified into three groups based on their palate depth. In patients with palatal depth > 22 mm, the mean inclination of molars was 7.4°; with palatal depth in the range of 19-22 mm, the mean inclination of molars was 5.23°; and with palatal depth < 19 mm, the mean inclination of molars was 2.9°. Results showed that there was a significant correlation between the buccolingual inclination of molars and the palate depth in vertical growers (P < 0.05). The buccolingual inclination of first molars is increased in patients with greater palatal depth. This parameter is helpful in classifying crossbites as skeletal or dental. The amount of compensation required to correct the cross bite can be adjusted using Korkhaus Index.

Prevalence and position of mandibular incisive canal, anterior loop of the mandibular canal and lingual foramen using cone beam computed tomography

Objective: Comprehensive knowledge about the anatomy of the surgical site is an important prerequisite for any surgical procedure. This study aimed to assess the prevalence, position and anatomical characteristics of mandibular incisive canal (MIC), lingual foramen (LF) and anterior loop of the mandibular canal (ALMC) in an Iranian population using cone beam computed tomography (CBCT). Materials and Methods: This study was conducted on 103 patients who underwent CBCT prior to implant placement. The CBCT scans of patients were evaluated by two observers to determine the visibility and length of MIC, LF and ALMC. The buccolingual inclination of MIC at the initiation point of canal and canal path were also studied. Results: The prevalence of MIC, LF and ALMC was 90%, 76% and 84% on CBCT scans, respectively. The mean length of MIC and ALMC was 7.5mm and 1.2mm, respectively and the mean width of LF was 0.9mm. The MIC had a buccal inclination at the initiation point and approximated the lingual plate as extended towards the midline. Analytical statistics including independent samples t-test, paired samples t-test, ANOVA analyses were applied. Conclusion: Considering the high prevalence of MIC, ALMC and LF and wide range of MIC (1.2mm to 20mm) and ALMC (1mm to 9.9mm) length, CBCT is recommended for patients prior to surgical procedures in the anterior mandible to determine the exact location of these anatomical structures.

Buccolingual Inclination Effects of Self-Ligating and Conventional Premolar Brackets: A Cone Beam Computed Tomography Study.

This study aimed to compare the effects of passive self-ligating (PSL) and conventional ligating (CL) of brackets on the buccolingual inclination (BLINC) of the maxillary premolars. This in vitro study included a PSL bracket group and a CL bracket group. Acrylic teeth on typodonts were aligned using 0.014-inch heat-activated nickel titanium (HANT) (T1) and 0.019×0.025-inch HANT (T2) and 0.021×0.025-inch stainless steel (SS) (T3) archwires in a sequence. Standardized cone beam computed tomography (CBCT) images were taken immediately after each archwire stage. The differences of premolar teeth BLINC values in the 0.019×0.025-inch and 0.014-inch HANT archwires (T2-T1) and 0.021×0.025-inch SS and 0.019×0.025-inch HANT archwires (T3-T2) were compared between PSL and CL groups. The value of p < 0.05 was considered statistically significant. The BLINC change of the second premolar (SPM) showed a statistically significant difference (p=0.008), but the BLINC change of the first premolar (FPM) (p=0.056) between the groups showed no statistically significant difference during the T2-T1 stage. However, there were statistically significant differences between two groups in the BLINC of the FPM (p=0.032) and SPM (p=0.032) in the T3-T2 stage. The angular changes in the buccal direction in the PSL group were higher than those in the CL group. The PSL upper premolar brackets used with the 0.021×0.025-inch SS archwire produced more buccal crown movement of the upper PM teeth compared with that of the CL brackets.

Orthodontic Treatment Characteristics and Outcomes in an Educational Setting.

Background To assess and correlate orthodontic treatment characteristics and outcomes in an educational setting. Methods A total of 287 patients were included. Independent chart reviews were conducted to gather demographic and pretreatment diagnostic information. Posttreatment digital records were graded with the ABO C-R Eval and the CCA methods. Pearson correlation coefficients were calculated to determine associations between variables. Results Of the 287 patients, 122 (42.5%) were male and 165 (57.5%) were female. The total average treatment time was 33.87 ± 10.28 months, with a range from 11 to 75 months. The mean ABO C-R Eval score was 29.10 ± 8.59 points. The parameters with the highest scores were buccolingual inclination and occlusal contacts. The mean CCA score was 3.36 ± 2.05 points. The highest scores were recorded for dental esthetics and management of the periodontium. Higher ABO DI scores were weakly correlated with longer treatment times (r = 0.258; p < 0.001). ABO C-R Eval scores showed a weakly significant association with treatment duration (r = 0.162; p=0.006), while CCA scores were moderately associated with treatment duration (r = 0.451; p < 0.001). Conclusions As treatment duration increased, the total ABO C-R Eval and CCA scores tended to increase; thus, quality of treatment outcomes decreased. A significant positive correlation was also found with the ABO DI score and treatment duration.

Assessment of buccal and lingual alveolar bone thickness and buccolingual inclination of maxillary posterior teeth in patients with severe skeletal Class III malocclusion with mandibular asymmetry

The purpose of this study was to evaluate the buccal and lingual alveolar bone thickness and buccolingual inclination of maxillary posterior teeth in patients with severe skeletal Class III malocclusion with and without mandibular asymmetry and compare with those in patients with skeletal Class I malocclusion. Cone-beam computed tomography images of 69 patients with severe skeletal Class III malocclusion and 30 patients with skeletal Class I malocclusion were collected and reconstructed with Dolphin 3D software. Based on the distance from menton to the sagittal plane (d), the patients with skeletal Class III malocclusion were divided into a symmetry group (d≤2mm) and an asymmetry group (d≥4mm). Buccal and lingual alveolar bone thickness and buccolingual inclination of maxillary posterior teeth were measured and compared. Correlations among dental measurements, severity of sagittal discrepancy, and mandibular deviation were analyzed. Maxillary posterior teeth on the deviated side in Class III asymmetry group and symmetry group were buccally inclined compared with the Class I group (P<0.001). A significant negative correlation was noted between buccolingual inclination of maxillary posterior teeth and ANB value with Spearman correlation coefficient of maxillary first molar, second premolar, and first premolar of -0.687, -0.485 and -0.506, respectively (P<0.001). Maxillary first molar showed thinner buccal alveolar bone on deviated side in asymmetry group and symmetry group of Class III, compared with the Class I group, with average values of 1.21mm, 1.19mm, and 1.83mm, respectively (P<0.05). The maxillary first premolar also showed thinner buccal alveolar bone on deviated side in Class III asymmetry group compared with the Class I group, with average values of 0.87mm and 1.28mm, respectively (P<0.05). Decompensation of buccally inclined posterior teeth in patients with skeletal Class III malocclusion should be more cautious owing to thinner buccal alveolar bone to avoid a high risk of fenestration and dehiscence.

Are clear aligners as effective as conventional fixed appliances?

Design Systematic reviewStudy population Orthodontic patients undergoing treatment with removable thermoplastic retainers compared with conventional fixed orthodontic appliances. The mean age of patients was between 15 and 33 years. Data sources Six electronic databases including: Scopus, Web-of-Science, PubMed, Cochrane, Clinical Trials and Grey Literature were searched in addition to a search of references in eligible studies with no restriction of language. Out of 559 studies, 55 were eligible. Only four articles were included; three non-randomised and one randomised controlled trial (RCT) involving 96-182 patients. The studies included were completed within 2005-2016.Study selection Clinical trials involving orthodontic patients undergoing treatment using thermoplastic removeable aligners, namely Invisalign, in comparison to conventional fixed orthodontic appliances of either self-ligating or tip-edge bracket systems were included.Data extraction and synthesis Two members of the research team independently selected articles which fulfilled the inclusion criteria and compared results prior to data collection. A third party examiner was available to resolve disagreements. The study quality was analysed for presence of bias; three non-randomised studies were evaluated and scored using the Methodological Index for Non-Randomised Studies (MINORS), one study was considered high methodological quality, two were considered moderate. The RCT was assessed using the Cochrane Collaboration Common Scheme for Bias and was deemed to be low risk of bias. Results The results suggest that Invisalign can provide successful alignment, however, it poses difficulties in achieving occlusal contacts, buccolingual inclination and vertical movement of teeth. One study found that Invisalign cases are more susceptible to relapse, which can be explained through the tipping mechanism compared to bodily movement, of conventional fixed appliances. Furthermore some studies show that although using aligners can result in overall shorter treatment time the final occlusion was not favourable. The outcome of the RCT, showed that aligners can be successful in treating class I malocclusions in extraction cases.Conclusions This systematic review found that the use of clear aligners made no significant difference to treatment time compared with conventional appliances. Additionally, removable aligners were effective in crowding cases but had limitations in achieving favourable outcomes in the anterior-posterior position and final occlusion, as well as being more likely to relapse post treatment.

Buccolingual Inclination of Maxillary and Mandibular First Molars in Untreated Adults: A CBCT Study

Buccolingual Inclination of Maxillary and Mandibular First Molars in Untreated Adults: A CBCT Study

Relationship between pre-treatment orthodontic case complexities and their treatment outcomes

PurposeTo determine whether pre-treatment orthodontic case complexities were associated with their treatment outcomes in each category of malocclusion. Materials and methodsTwo hundred orthodontic cases treated with edgewise appliances from university clinic that satisfied requirements for the certification were studied. The Discrepancy Index (DI) and the Objective Grading System (OGS) were calculated. The relationship between these measurements was evaluated using Pearson’s correlation coefficient. ResultsThe mean DI score was 23.67 ± 10.30, and the mean OGS score was 19.92 ± 6.92. Statistically, there was only a weak and insignificant correlation between the DI and OGS (r = 0.055, p > 0.05). Buccolingual inclinations and interproximal contacts were components that had the highest and lowest mean OGS scores respectively. ConclusionMalocclusion complexity was not associated with orthodontic treatment outcomes. Cases which underwent two-phase treatment were found to have the most complex pre-treatment malocclusion and also the most unsatisfactory clinical outcomes. The OGS component with the highest discrepancies was buccolingual inclinations.

Evaluation of Growth and Development of Late Mixed Dentition Upper Dental Arch with Normal Occlusion Using 3-Dimensional Digital Models.

Objective The purpose of this study was to observe the three-dimensional growth and development of the maxillary arch in 10-year-olds with normal occlusion during the late mixed dentition stage. Methods Forty-four 10-year-old students (22 males and 22 females) who had normal occlusion during late mixed dentition were selected from an elementary school in Beijing, China. Once per year for three consecutive years, a dental cast was obtained from each subject, and the cast was scanned with a 3D digital scanner (R700 3D). The three-dimensional measurements of the maxillary dental arch and the inclination of the bilateral maxillary first molars were obtained from the digital model. Results The upper anterior arch length (UAAL), upper total arch length (UTAL), upper inter primary or permanent canine width (UICW), upper intermolar width (UIMW), and upper dental arch length (UDAL) increased by 0.959 mm, 0.583 mm, 0.955 mm, 1.462 mm, and 2.46 mm, respectively, over the two years (P < 0.001). UR6BL and UL6BL decreased by 4.416° and 7.133°, respectively, over the two years (P < 0.001). The values of the UICW and UIMW were 1.67 mm and 1.86 mm, respectively, larger in males than in females at 12 years old (P < 0.01). The change in the UTAL was 0.431 mm greater in males than in females over the 2 years (P < 0.05). Conclusion The UAAL, UTAL, UICW, UIMW, and UDAL in 10- to 12-year-olds with normal occlusion increased with age. The buccolingual inclination of the bilateral maxillary first molars inclined to the palatal side with age. The UICW and UIMW were larger in males than in females at 12 years old. The male UTAL increased more than the female UTAL over the 2 years.

Comparison of anterior mandibular alveolar thickness and height in young adults with different sagittal and vertical skeletal relationships: A CBCT Study

Alveolar bone surrounding mandibular incisors dictates the range of buccolingual inclination that can be achieved with treatment. The objective of this study was to evaluate the mandibular anterior alveolar thickness and height in individuals with different sagittal and vertical skeletal relationships. Cone beam computed tomography scans of 53 individuals (22 males and 31 females; mean age 21.19±3.7 years) were classified into 3 groups according to the sagittal skeletal relationship (class I, class II, and class III) and the vertical growth pattern (hyperdivergent, normodivergent, and hypodivergent). The alveolar thickness and height of both mandibular central incisors were measured. Group comparisons were performed with analysis of variance and post hoc Scheffé tests. Multiple linear regression was applied to evaluate the influence of all variables on the alveolar conditions. Alveolar thickness and height showed no significant differences among the class I, II and III groups (6 and 7mm regardless of the sagittal group, P>0.05). The middle and lower alveolar thicknesses were significantly smaller in hyperdivergent (5.76mm and 6.34mm) and normodivergent (6.29mm and 7.40mm) than hypodivergent individuals (6.63mm and 8.27mm respectively). The lingual alveolar height was smaller in hyperdivergent (6.04mm) than hypodivergent individuals (7.93mm) (P=0.029, 95%CI: 0.15-3.63) and the lingual bone height was smaller in hypodivergent (3.24mm) than hyperdivergent individuals (5.06mm) (P=0.029, 95%CI: 0.15-3.48). Multiple linear regression indicated a significant influence of the root length on the alveolar thickness and height. The sagittal skeletal relationship showed no influence on the alveolar thickness or height, even if dental compensation was present. Hyperdivergent individuals showed smaller alveolar thicknesses and heights than hypodivergent individuals.

Effectiveness of clear aligner therapy for orthodontic treatment: A systematic review.

To analyse through a systematic review the effectiveness of clear aligners by assessing: (a) predictability of clear aligners and (b) treatment outcome comparison of clear aligner therapy with fixed appliance therapy. An electronic search was made from January 2014 to April 2019 using MEDLINE, Embase, Web of Science and LILACS databases without any limitations on language. Three reviewers independently assessed the articles. Quality assessment of observational studies and randomized control trial was done by using the ROBINS tool and Cochrane risk of bias tool, respectively. GRADE instrument was used to assess certainty level for each identified outcome. Seven eligible articles (one randomized controlled trial and six retrospective cohort) were included in our systematic review. Most of the studies (six out of seven) had a moderate risk of bias and one had a high risk of bias. 'Low to moderate level' of certainty in regard to specific clear aligner therapy tooth movements' efficiency was identified. Clear aligners may produce clinically acceptable outcomes that could be comparable to fixed appliance therapy for buccolingual inclination of upper and lower incisors in mild to moderate malocclusions. However, not all potential clinical scenarios have been assessed in the included studies. Most of the tooth movements may not be predictable enough to be accomplished with only one set of trays with clear aligners despite the recent advances in technology.

A Study of the Quality of Finish of Lingual versus Labial Bracket Systems As Measured By the Objective Grading System: A Retrospective Study in a University Orthodontic Clinic

Objective: The purposes of this study were to determine the quality of final orthodontic treatment outcome and average treatment time with fixed lingual brackets compared to labial brackets. Our hypothesis was that labial fixed appliances produce a higher quality of final treatment outcome, and a shorter average treatment time compared to lingual fixed appliances. Materials and Methods: This was a retrospective study of matched pairs. Records of twenty subjects treated with lingual appliances were included. These were paired with twenty patient records of subjects in fixed labial appliances with matching initial discrepancy index (DI) (±5 points), Angle classification (within one-half step), number of extracted teeth, and age. Final models were scored using the eight criteria of the American Board of Orthodontics’ Objective Grading System (OGS) and treatment time was recorded in number of days. Results: The mean difference in OGS scores between groups was 2.00 ± 8.89 points with a mean OGS score of the labial and lingual fixed appliance groups of 21.6 ± 7.45 and 19.6 ± 6.43, respectively. This difference was not statistically significant (p = 0.33). Lingual subjects’ treatment time was an average of 4.25 ± 213.78 days less compared to their matched labial subjects. This difference was not significant (p = 0.93). A statistically significant difference was found in the buccolingual inclination subcategory of the OGS. The mean difference in the buccolingual inclination score of lingual subjects was 1.90 ± 3.52 points higher than labial subjects (p = 0.03). Conclusion: Lingual fixed appliance subjects had no significant difference in treatment time and / or treatment outcome as measured by OGS when paired with labial fixed appliance subjects, however, they did have significantly higher buccolingual inclination discrepancies.

Efficacy of the mini tooth positioner in improving orthodontic finishes.

The primary objective of this study was to assess the effectiveness of the mini tooth positioner in improving the quality of orthodontic treatment outcomes, as measured by the American Board of Orthodontics (ABO) cast-radiograph evaluation (CRE). Thirty patients were treated prospectively with a minipositioner for 4-6weeks immediately after debond. Sixteen patients who had received a maxillary vacuum-formed retainer (VFR) and fixed mandibular canine-to-canine retainer at time of debond were enrolled retrospectively as control subjects. Models from time of debond (T1) were graded with the use of the ABO CRE and compared with models obtained 4-6weeks after debond (T2) for each group. For the minipositioner group, the overall CRE score improved significantly by an average of 6.77 points. Significant improvements were noted in the categories of alignment and rotations (-0.68), marginal ridges (-1.40), buccolingual inclination (-0.45), overjet (-0.97), and occlusal contacts (-3.00). For the control group, overall CRE score improved significantly by an average of 1.16 points. Only the categories of overjet (-0.38) and occlusal contacts (-1.22) showed significant improvements. The minipositioner is an effective tool in improving the overall finish of orthodontic treatment. In the 4-6weeks after debond evaluated in this study, the minipositioner significantly outperformed the maxillary VFR/mandibular fixed canine-to-canine retainer in improving final treatment outcomes.

Diagnosis of transverse problems

Traditionally, maxillary and mandibular skeletal widths and buccolingual inclination of posterior teeth are evaluated by using posteroanterior (PA) cephalogram and dental casts. However, it is difficult to identify the landmarks and make a diagnosis due to the superimposed structures on the PA cephalogram. As for the dental casts, they can neither reveal skeletal dimensions of maxilla and mandible, nor the root positions in the alveolar bone. Nowadays, the advent of CBCT enables clinicians to view craniofacial structures in three planes of space without any obstruction or superimposition of structures. In this article, a CBCT analysis on the transverse dimension is introduced. The maxillary and mandibular skeletal widths at different tooth levels, buccolingual inclination of each tooth, and their root positions in the alveolar bone can be determined. Thus, a proper transverse diagnosis can be made.