Incisor Mandibular Plane Angle Research Articles

Retention efficacy and patient experience with customized clear retainer and wrap-around circumferential retainer among non-extraction orthodontic patients: A 12-month follow-up cohort study.

The aim of this study was to evaluate retention efficacy by assessing retention stability and patient perspectives according to type of circumferential retainer: the wrap-around circumferential retainer (WCR) and customized clear retainer (CCR). This cohort follow-up study involved 52 patients aged 18-62 who underwent fixed-appliance orthodontic treatment without extractions or orthognathic surgery. Following screening consenting participants were divided into WCR and CCR groups. All participants before follow-up received fixed retainers for the upper and lower anteriors and respective removable retainers within 2 weeks post-debond. Intraoral scans and lateral cephalograms were taken immediately after debonding (T0) and again 12 months later. Dentoalveolar changes in several measurements were compared to evaluate retention efficacy. Surveys were conducted at 1 month (T1) and 12 months (T2) post-debonding to assess changes in patient experiences. Outcome assessments were blinded. Paired T-tests and independent T-tests were used for intragroup and intergroup comparisons of dentoalveolar measurements, respectively. Survey responses were analysed using the Pearson Chi-Square test. The final assessment included 32 participants. Model analysis revealed no significant differences between the groups, except for maxillary intermolar width (p = .033). In the WCR group, the cephalometric analysis indicated a significant increase in the incisor mandibular plane angle (p = .002) and a decrease in the interincisal angle (p = .014), while changes in the CCR group were statistically non-significant. Patient attitude evaluation showed similar trends for wear time and overall satisfaction. However, a higher percentage of respondents in the WCR group reported irritation when wearing the retainers (p = .037) at T1 and discomfort related to speech (p = .038) at T2. CCR showed better retention efficacy in terms of lower incisor inclination. Patients experienced relatively less irritation and speech discomfort with CCRs.

Evaluation of the correlation of mandibular ramus to base ratio with mandibular incisor angulation: A cephalometric study

: The cephalometric evaluation of an individual case using floating norms is the contemporary approach in orthodontic diagnosis. This study aimed to evaluate the correlation of mandibular ramus to the mandibular base ratio with mandibular incisor proclination in a mixed Indian population.A total of 100 cephalograms were selected from the archives of the department of orthodontics fulfilling inclusion and exclusion criteria.The mean age of cases studied was 17.09 ± 2.61 years, with an age range of 13–26 years. The sample comprised 47 males and 53 females. The results of this study showed that the higher incisor mandibular plane angle (IMPA) has statistically and clinically significant association with a higher ramus to mandibular base ratio in both male and female groups. The unit increase in IMPA is significantly associated with a 0.004 unit increase in the ratio of ramus to mandibular base. This study concludes that the IMPA and ratio of ramus to mandibular base are the closest counterparts of each other and explains the variations in the IMPA even in the population group with similar skeletal characteristics. These two components interacts with each other to give a balanced occlusion and function.

The second molar dilemma in orthodontics: to bond or not to bond?

To compare orthodontic treatment (OT) outcome in adolescents undergoing nonextraction fixed OT with or without bonding of second molars using the score of the American Board of Orthodontics Cast Radiograph Evaluation (C-R-Eval). This study included healthy adolescents with skeletal Class I or mild Class II/Class III malocclusion, normal or deep overbite (OB), and mild-to-moderate dental crowding (<5 mm) who underwent nonextraction fixed OT with ("bonded" group) or without ("not-bonded" group) bonding of second molars. Patient treatment records, pre- and posttreatment digital models, lateral cephalograms, and orthopantomograms were assessed. The evaluated outcomes included leveling of the curve of Spee (COS), OB, control of incisor mandibular plane angle (IMPA), number of emergency visits (related to poking wires and/or bracket failure of the terminal molar tubes), treatment duration, and C-R-Eval. Treatment variables were compared across time points and among groups. The sample included 30 patients (mean age 16.07 ± 1.80 years) in the bonded group and 32 patients (mean age 15.69 ± 1.86 years) in the not-bonded group. The mean overall C-R-Eval score was significantly higher (P < .001) in the not-bonded group (25.25 ± 3.98) than in the bonded group (17.70 ± 2.97). There were no significant differences in mean changes of COS, OB, IMPA, or treatment duration among groups. The mean number of emergency visits was significantly higher in the bonded (3.3 ± 0.6) than the not-bonded group (1.9 ± 0.4) (P < .001). Bonding of second molars enhances the outcome of nonextraction fixed OT as demonstrated by the C-R-Eval without increasing treatment duration, irrespective of more emergency visits.

Influence of differences in mandibular incisor inclination on skeletal stability after orthognathic surgery in patients with skeletal class III malocclusion

Objective: The preoperative inclination angle of mandibular incisors was crucial for surgical and postoperative stability while the effect of proclined mandibular incisors on skeletal stability has not been investigated. This study aimed to evaluate the effects of differences in presurgical mandibular incisor inclination on skeletal stability after orthognathic surgery in patients with skeletal Class III malocclusion.Methods: A retrospective cohort study of 80 consecutive patients with skeletal Class III malocclusion who underwent bimaxillary orthognathic surgery was conducted. According to incisor mandibular plane angle (IMPA), patients were divided into 3 groups: retroclined inclination (IMPA < 87°), normal inclination (87° ≤ IMPA < 93°) and proclined inclination (IMPA ≥ 93°). Preoperative characteristics, surgical changes and postoperative stability were compared based on lateral cephalograms obtained 1 week before surgery (T0), 1 week after surgery (T1), and at 6 to 12 months postoperatively (T2).Results: The mandible demonstrated a forward and upward relapse in all three groups. No significant differences in skeletal relapse were observed in the 3 groups of patients. However, the proclined inclination group showed a negative overbite tendency postoperatively compared with the other two groups and a clinically significant mandibular relapse pattern. Proclined IMPA both pre- and postoperatively was correlated with mandibular relapse.Conclusion: Sufficient presurgical mandibular incisor decompensation was of crucial importance for the maintenance of skeletal stability in patients with skeletal Class III malocclusion who subsequently underwent orthognathic surgery.

Alveolar bone changes in the mandibular incisors after genioplasty, a three-dimensional study

IntroductionFunctional genioplasty aims to achieve lip competence at rest and reduces lip pressure against the mandibular incisors. The purpose of this study was to describe the radiographic changes in alveolar bone of the mandibular incisors after functional genioplasty. Materials and methodsCone beam CT images from 36 patients were compared between immediate (T0) and delayed postoperative period (T1). The mean time to complete the second imaging was 10.9 ± 4.7 months. Dental and bone parameters were assessed: the vestibular bone height (BH), the bone thickness (BT) with regard to the apex of the central incisor (BT2) and at equidistance between the cementoenamel junction and the dental apex (BT1). The existence of fenestrations, the apical-root resorption and the incisor-mandibular plane angle (IMPA) were also collected. ResultsNo significant change occurred in the BH. BT was improved of a mean 47.9% and 53.6% at the BT1 level on #31 and #41, respectively (p1=0.01 and p2=0.02, respectively); and of 53.0% at the level of the apex of both mandibular central incisors (p1=0.003 on #31 and p2=0.009 on #41). No difference in the number of fenestrations was observed between T0 and T1. A significant decrease in the root length on both mandibular incisors was observed on the delayed CBCT (from 21.96 ± 1.35 to 21.68 ± 1.32 mm for #31, p=0.0007; from 22.26 ± 1.66 to 21.96 ± 1.48 mm for #41, p=0.002). Finally, the IMPA remained stable between the two examinations with a mean 106.1 ± 7.38° vs 105.8 ± 6.51° (p=0.38). ConclusionFunctional genioplasty favours the alveolar bone formation of the mandibular central incisors, probably by direct bone grafting, but also by the relaxation of the perioral and chin musculature.

Comparative study of changes in the airway dimensions following the treatment of Class II malocclusion patients with the twin-block and Seifi appliances.

Functional appliances are frequently used to stimulate mandibular growth in cases of Class II malocclusion with mandibular deficiency. Many studies have reported improved pharyngeal airway passage (PAP) dimensions following functional appliance therapy in children. The present study aimed to assess changes in the airway dimensions following the treatment of Class II malocclusion patients with the twin-block and Seifi appliances. Lateral cephalograms of 37 patients with Class II malocclusion and mandibular deficiency treated with the twin-block appliance (n = 20) or the Seifi appliance (n = 17) were assessed in this before-and-after study. The preoperative and postoperative lateral cephalograms were compared to determine changes in the airway dimensions at the level of the palatal plane (PP), the occlusal plane (OP) and the 2nd-4th cervical vertebrae (C2-C4) in the 2 groups. The results were analyzed with the t test and the one-way analysis of covariance (ANCOVA). After treatment, significant changes occurred in the point A-nasion-point B (ANB) and sellanasion-point B (SNB) skeletal cephalometric indices in the twin-block appliance group, and in ANB, SNB and incisor-mandibular plane angle (IMPA) in the Seifi appliance group. The airway dimensions at the level of PP, OP and the 3rd cervical vertebra (C3) significantly increased postoperatively as compared to the baseline in the twin-block appliance group (p < 0.05). The increases in the airway dimensions at the level of PP and C3 in the twin-block appliance group were significantly greater than in the Seifi appliance group (p < 0.05). The treatment of Class II Division I malocclusion with the twin-block appliance significantly increased the airway dimensions at the level of PP, OP and C3, whereas the Seifi appliance did not cause any significant changes in the airway dimensions.

Lower incisor inclination and thickness of the alveolar process and mandibular symphysis in the development of gingival recession: A retrospective cohort study

IntroductionRetrospective studies have found conflicting results regarding the relationship between lower incisor inclination and the development of gingival recession (GR) after orthodontic treatment. ObjectiveThis study aimed to investigate the relationship between lower incisor inclination and alveolar process (AP) and mandibular symphysis (MS) thickness in the development of GR. Materials and MethodsFrontal intraoral photography and cephalometric radiography were conducted before (T0) and after (T1) orthodontic treatment of 62 subjects. The presence of GR was considered when the cementoenamel junction was visible in the lower incisor on the frontal intraoral photograph.The circumstances for improvement, stability, and worsening of the gingival situation were based on the reduction, maintenance, and increase in the number of lower incisors with GR before and after treatment. To measure the incisor-mandibular plane angle (IMPA) andthe thickness of the AP and the MS were used the cephalometric radiographs. ResultsMen had a significantly thicker MS than women at T0 and T1 (p < 0.0004).There was a significant reduction of approximately 10% in AP between T0 and T1 (p < 0.0001).Among subjects without GR at T0, 70.4% presented a stable gingival situation at T1. For subjects with 1 lower incisor with GR at T0, 50% showed improvement in the gingival situation at T1, 21.4% remained stable, and 28.6% experienced worsening.Sixteen lateral incisors presented a worsening gingival situation, representing an increase of 129% compared to the central incisors. ConclusionNo relationship was found between lower incisor inclination and the thickness of the AP and MS in the development of GR.

Treatment change comparisons between skeletal Class I and II white adolescents with 3 different vertical divergencies—part 1: Frankfort-Mandibular Incisor Angle (FMIA) and soft-tissue profile

This study investigated the interrelationship between FMIA and soft-tissue profile changes in skeletal Class I and II white adolescents with 3 different vertical skeletal patterns. Two hundred seventy cephalometric images were constructed from pretreatment and posttreatment cone-beam computed tomography images of 135 white adolescents (69 females and 66 males with a mean age of 12.8 ± 1.4 years pretreatment and 15.0 ± 1.4 years posttreatment). SNA, SNB, ANB, Frankfort Mandibular Angle [FMA], Incisor Mandibular Plane Angle [IMPA], Frankfort-Mandibular Incisor Angle [FMIA], and Z angle were measured. A mixed-model analysis of variance was performed for patients with an increased posttreatment Z angle to evaluate within-subject and between-subject effects of variables in relation to horizontal and vertical skeletal patterns. Post-hoc tests were conducted to identify statistical significance among the 3 different divergent subgroups. Patients with a skeletal Class I relationship had straighter facial profiles and a larger FMIA than patients with a skeletal Class II relationship before and after treatment. FMA, FMIA, IMPA, and Z angle treatment changes were similar between the skeletal Class I and II groups. The final FMIA means of the 3 divergent subgroups converged at 65° in the skeletal Class I group and 60° in the skeletal Class II group. The mandibular incisors were uprighted during treatment in the hyperdivergent patients whose Z angle values increased after treatment. Horizontal skeletal relationships seem more suitable for determining the desired FMIA in Tweed's total space analysis than vertical skeletal divergencies.

Assessment of Changes in Craniofacial Structures, Bite Force and Periodontal Status Following Fixed Functional Appliance Therapy

The aim of this study was to determine the effect of Forsus Fatigue Resistant Device (FRD) appliance on craniofacial structures, bite force and periodontal status in Class II malocclusion patients. In this prospective interventional follow-up study, thirteen (13) Class II Division 1 patients in their post-adolescent age group with average age of 17.10 ± 1.63 year was treated with Forsus FRD. They were assessed for craniofacial changes, bite force and periodontal status at baseline, after alignment and leveling, after removal of FRD. Improvement in soft tissue profile was due to significant dentoalveolar changes. There were significant decreases in overjet, overbite, reference line to upper first molar, H angle (p<0.001) and significant increases in upper lip to E-line, reference line to lower molar and angular measurements like nasolabial angle, U1 to SN plane, Incisor Mandibular Plane Angle (p<0.001). The bite force was significantly decreased on the molar and the incisor region (p<0.001). A significant increase in plaque index (PI), gingival index (GI), probing pocket depth was noticed without any significant clinical attachment loss. Class II correction with Forsus FRD appliance was mainly due to significant dentoalveolar changes. Skeletal changes were non-significant. A decrease in the bite force was found with FRD. The magnitude of bite force was more in males compared with females. The increase in GI, PI, pocket probing depth implies the necessity of oral hygiene and plaque control measures. However, there was no significant change in clinical attachment level.

Complex case treatment: Is there a limit for surgery-first approach?

Are there any limits for Surgery-first approach? the article strives to identify the tenets of effective management of complex cases, such as facial asymmetry, with surgery-first approach. The main purpose of the article is in attempting to itemize prerequisites or determining factors, through various degrees of facial asymmetry severity, for the successful management of facial asymmetry cases. The key factors such as (1) assessment of chin deviation, (2) quantification or discernment of transverse occlusal plane canting, (3) spatial orientation evaluation of differential anterior and posterior region transverse occlusal canting, and (4) contemplations of six degrees of freedom (6DoF) (translation movements combined with rotation axis - pitch, roll and yaw) are evaluated. Furthermore, dental alignment, severity of mandibular and maxillary occlusal (anterior and posterior) plane canting, critical cephalometric parameters, such as, incisor mandibular plane angle, and other vital sub- components of facial asymmetry are analysed, in detail. Subsequently, these are coherently synchronized with the maxillomandibular complex (MMC) rotation surgery during planning for the successful execution of facial asymmetry correction. Additionally, the article describes the (1) usage of orthodontic arch wires, (2) selection criteria of specific surgical osteotomies, and (3) coordination of maxillary and mandibular dentition to establish a transitional or treatable malocclusion. In conclusion, a thorough evaluation of the determining factors, as described in the article, for the correction of facial asymmetry with surgery-first, aid in categorising facial asymmetry cases that require minimal pre-surgical orthodontics or without pre-surgical orthodontic treatment, thereby defining the limits of surgery-first.

Elastodontic treatment with oral bio-activators in young children.

Elastodontic therapy can correct bad oral habits and malocclusions in young patients by guiding jaw growth, eliminating functional disorders, and improving tooth position. The aim of this study was to assess the effects of bio-activator therapy on the presence of atypical swallowing with tongue thrust in growing patients. A retrospective study was conducted. Data regarding the early orthodontic treatment of 40 consecutive patients with atypical swallowing and tongue thrust (23 males and 17 females) were assembled from January 2019 to January 2020. All patients (≥7 and ≤15 years of age) were monitored for 1 year in a private practice in Isernia, Italy. The mean age at commencement of orthodontic treatment was 8.5 years (range=7.1-14.9 years), and the mean total duration of therapy was 1 year (range=11 months-1 year). Final lateral radiographs demonstrated a mean of improvement of 8° for upper and lower incisor proclination (I/SN) and 3.5° for incisor mandibular plane angle (IMPA) in 36 patients, and 5° of I/SN and 2° of IMPA in the remaining 4 children after 1 year of treatment. Bad oral habits in younger patients must not be ignored. The duration of treatment can differ depending on the severity of the open bite and the patient's cooperation. This study demonstrates the short-term efficacy of these myofunctional appliances in the treatment of atypical swallowing. In order to quickly eliminate factors which endanger healthy development of dento-skeletal structure, it is important to closely monitor patients during their development phase.

Does Clockwise Rotation of Maxillomandibular Complex Using Surgery-First Approach to Correct Mandibular Prognathism Affect Surgical Movement and Stability?

Orthognathic surgery (OGS) using the surgery-first approach (SFA) can decrease treatment time and increase patient satisfaction. Clockwise rotation (CWR) of the maxillomandibular complex to correct mandibular prognathism leads to optimized functional, aesthetic, and stable outcomes. This study examined the combined effect of SFA and CWR of the maxillomandibular complex to correct mandibular prognathism by comparing the surgical movement before (T0) and immediately after OGS (T1) and the stability between T1 and 12 months after OGS (T2). This prospective cohort study enrolled patients with skeletal Class III malocclusion who underwent SFA involving Le Fort I osteotomy and bilateral sagittal split osteotomy, with or without genioplasty. Based on the occlusal plane (OP) change at T0-T1, the patients were divided into CWR (OP>4°) and control (C) groups (OP≤4°). The predictor variable was OP change at T0-T1. The primary outcome variable was the stability of pogonion (Pog) at T1-T2. The covariates included demographic factors, cephalometric measurements (anterior facial height, posterior facial height, OP, mandibular plane angle, incisor mandibular plane angle, overjet, and overbite), and 3-dimensional landmark displacement (anterior nasal spine, A-point, upper central incisor, upper first molar, lower central incisor, lower first molar, Pog, gonion, and condylion). An independent t-test was used to compare between these 2 groups when appropriate. The level of significance was set at P<.05. The sample included 28 patients (17 females) in the C group and 36 (24 females) in the CWR group; the mean ages were 23.89±3.35 and 24.08±4.02years, respectively. For the surgical movement at T0-T1, the CWR group showed an association with vertical movement of the maxilla at posterior nasal spine (P=.005), anterior nasal spine (P<.001), and A-point (P<.001) and horizontal backward movement of the mandible at B-point (P<.001), Pog (P<.001), and gonion (P=.042). At T1-T2, all landmarks remained stable without clinically significant difference between the 2 groups. Surgical movement in the CWR group could vertically displace the maxilla and setback mandible more than that in the C group. Postoperative skeletal stability remained the same between the 2 groups at 1year after OGS.

Assessment of chin morphology in different skeletal dysplasia - A cross-sectional study.

Objective:The objective of the study is to evaluate the morphology of the symphyseal region of adult skeletal Class II and Class III malocclusion as compared with Skeletal Class I subjects.Materials and Methods:The symphyseal width and height were evaluated using data from 80 lateral cephalograms of the age range of 18 years to 25 years. Average growing Skeletal Class II (n = 30) and Class III (n = 20) subjects were used as a comparison group. Average growing normal occlusion samples (n = 30) were used as controls.Results:Alveolar height was similar in all groups. The width of the symphyseal region including basal width, the width of the cervical region of the lower central incisor at the cementoenamel junction, and symphysis width were found to be similar in all groups. There is no significant difference in gonial angle in both Class II and III groups as compared to control. Articular angle showed no significant difference. Mandibular incisor dentoalveolar height (L1-AH) was found to be significantly higher in the Class II group (P < 0.05).Conclusions:There are no definite morphological differences in the symphyseal region between average grower Class I, Class II, and Class III skeletal malocclusions except mandibular incisor dentoalveolar height (L1-AH) and incisor mandibular plane angle which is higher whereas ramus length and body length which is lesser in Class II group as compared with controls. Width of the cervical region of the lower central incisor at the cementoenamel junction (Id-Id’) and incisor mandibular plane angle was lower than control in Class III subjects.

Characterization of phenotypes and predominant skeletodental patterns in pre-adolescent patients with Pierre-Robin sequence.

ObjectiveTo investigate the phenotypes and predominant skeletodental pattern in pre-adolescent patients with Pierre–Robin sequence (PRS).MethodsThe samples consisted of 26 Korean pre-adolescent PRS patients (11 boys and 15 girls; mean age at the investigation, 9.20 years) treated at the Department of Orthodontics, Seoul National University Dental Hospital between 1998 and 2019. Dental phenotypes, oral manifestation, cephalometric variables, and associated anomalies were investigated and statistically analyzed.ResultsCongenitally missing teeth (CMT) were found in 34.6% of the patients (n = 9/26, 20 teeth, 2.22 teeth per patient) with 55.5% (n = 5/9) exhibiting bilaterally symmetric missing pattern. The mandibular incisors were the most common CMT (n = 11/20). Predominant skeletodental patterns included Class II relationship (57.7%), posteriorly positioned maxilla (76.9%) and mandible (92.3%), hyper-divergent pattern (92.3%), high gonial angle (65.4%), small mandibular body length to anterior cranial base ratio (65.4%), linguoversion of the maxillary incisors (76.9%), and linguoversion of the mandibular incisors (80.8%). Incomplete cleft palate (CP) of hard palate with complete CP of soft palate (61.5%) was the most frequently observed, followed by complete CP of hard and soft palate (19.2%) and CP of soft palate (19.2%) (p < 0.05). However, CP severity did not show a significant correlation with any cephalometric variables except incisor mandibular plane angle (p < 0.05). Five craniofacial and 15 extra-craniofacial anomalies were observed (53.8% patients); this implicated the need of routine screening.ConclusionsThe results might provide primary data for individualized diagnosis and treatment planning for pre-adolescent PRS patients despite a single institution-based data.

Personalized Orthodontics: From the Sagittal Position of Lower Incisors to the Facial Profile Esthetics.

Background: One of the goals of orthodontic treatment is to obtain maximum facial harmony. The sagittal position of the lower incisors plays a significant role in the planning of orthodontic treatment. The aim of the study was to evaluate the relationship between the sagittal position of lower incisors and facial profile esthetics with reference to the skeletal vertical dimension. Methods: There were 200 patients included in the study. Patients were allocated into three groups, depending on the vertical growth pattern: normal-angle, low-angle, and high-angle cases. Tweed–Merrifield cephalometric analysis was used to assess the sagittal and vertical position of the mandible, as well as to assess the sagittal position of the lower incisors. Results: Z-angle and Frankfort mandibular incisor plane angle (FMIA) decreased significantly (p < 0.001) with the increase of the skeletal vertical dimension. Incisor mandibular plane angle (IMPA) was significantly higher (p < 0.001) in low-angle patients compared to the high-angle ones. Z-angle appeared to be the most accurate parameter (area under curve, AUC = 0.957) describing patients with a convex profile. The cutoff value of Z-angle 68.0° was characterized by the sensitivity of 94.1% and the specificity of 84.3%. Conclusions: The sagittal position of the lower incisors significantly affects the facial profile convexity. The Z-angle is the parameter which most accurately describes the patients with a convex profile.

Analysis of pretreatment factors associated with stability in early class III treatment

BackgroundThe purpose of this study was to identify pretreatment factors associated with the stability of early class III treatment, since most orthodontists start the treatment with their uncertain hypotheses and/or predictions. Subjects consisted of 75 patients with a class III skeletal relationship (ANB < 2° and overjet < 0 mm) who had been consecutively treated with rapid maxillary expansion and facemask and followed until their second phase treatment. The patients were divided into two groups according to whether they showed relapse in follow-up. The stable group maintained their positive overjet (n = 55), and the unstable group experienced relapse with a zero or negative overjet (n = 20). Two general, three dental, and 13 cephalometric pretreatment factors were investigated to determine which factors were associated with stability.ResultsSex, pretreatment age, and anteroposterior functional shift, which were hypothesized as associated factors, were not related to the stability of early class III treatment. Significant differences were detected between the two groups in the horizontal distance between the maxillary and mandibular molars in centric relation. Cephalometric variables, such as the mandibular length (Ar-Me), Wits appraisal, SN to ramus plane angle (SN-Rm), gonial angle, incisor mandibular plane angle (IMPA), and Frankfort plane to mandibular incisor angle (FMIA) showed significant differences between the groups. The horizontal distance was the most influential factor by logistic regression analysis.ConclusionsHypothesis (related to sex, age, functional shift) were rejected. Several cephalometric factors related to the mandible were associated with stability. The horizontal distance between the maxillary and mandibular molars in centric relation was the best predictor of early class III treatment relapse.

Retrospective comparison of dental and skeletal effects in the treatment of Class II malocclusion between Herbst and Xbow appliances

The purpose of this research was to compare dentoskeletal changes produced by Herbst and Xbow appliances in late mixed/early permanent dentition patients with Class II Division 1 malocclusion to an untreated control group. The retrospective cohort consisted of 41 patients treated with the Herbst appliance on average for 14months (mean age of 11.3years), 41 patients treated with Xbow appliance on average for 14months (mean age of 11.11years), and an untreated control sample of 25 patients followed on average for 21months (mean age of 11.9years). All patients had Class II Division 1 malocclusion characteristics. Lateral cephalometric radiographs were taken before and after phase 1 treatment/follow-up. Data were analyzed by an analysis of variance followed by Tukey post-hoc tests. Although there was a high equivalence among the groups in the pretreatment cephalometric values, 4 variables showed differences (U6-FHp, L6-FHp, LAFH, and PP-U1). When comparing the mean changes (before and after phase 1 treatment/follow-up), incisormandibular plane angle (IMPA), Wits appraisal, L6-FHp, Co-Pog, and PP-U1 measurements showed statistically significant differences. In addition, more relative mesial movement of the mandibular molars (an additional 2.4mm) and a larger increase in mandibular length (an additional 3.2mm) was noted for the Herbst group. Class II correction using Herbst and Xbow occurred in both groups through improvement in the maxillomandibular relationship and labial inclination of the mandibular incisors, as well as a relatively increased mesialization of the mandibular molars. Although both appliances improve occlusal features, the portrayed changes were not always similar. Herbst seems to produce more mandibular size increase over a similar treatment period.

Evaluation of Cephalometric Standards for Zanjanian Population According to Downs' Analysis

Background: Following the morphological features of different races and ethnic groups, knowledge of standard dentofacial patterns of each ethnic group is essential. Therefore, this study aimed to explain cephalometric standards for the Zanjanian population according to Downs' analysis and compare them to Caucasian individuals. Methods: Seventy lateral cephalometries of Zanjanian adults (17 - 29 years old) who had been referred to a private orthodontic office in Zanjan, Iran with class I molar and canine relationship and normal overjet and overbite as well as minimum crowding/spacing/rotations were scanned and traced with the Novatech scanner and Dolphin software version 10. Next, statistical analyses were performed in order to compare the Zanjanian population to Caucasians. Results: We found a significant difference between males and females in terms of interincisal angle, incisor-occlusal angle, incisor-mandibular plane angle, upper incisor proclination, facial angle, and angle of convexity. Discussion: The analysis of six statistically significant parameters indicates that the upper and lower incisors in women of Zanjan were proclined and protruded compared with those of Caucasian subjects. Due to the statistical analysis on facial angle and angle of convexity, women also show more maxillary prognathism and skeletal class II pattern. Generally, a comparison of Zanjanian population cephalometrics based on Downs' analysis showed an increase in maxillary prognathism, maxillary and mandibular incisal protrusion and posterior rotation of the mandible. Conclusions: In conclusion, the Zanjanian population tends to have more dental and skeletal class II patterns than the Caucasians. In addition, gender comparison indicates lower and upper-incisors protrusion in women of Zanjan.

A comparison of treatment results of adult deep-bite cases treated with lingual and labial fixed appliances.

To compare the cephalometric treatment results of adult deep-bite cases after labial and lingual fixed orthodontic treatment. A total of 102 patients underwent lingual orthodontic treatment and complete records were evaluated. The following inclusion criteria were used: patients who had Angle Class I or mild Class II malocclusion; comprehensive orthodontic treatment that did not include intrusion mechanics or any extractions; patients with an initial overbite of more than 3.7 mm. Thirteen patients met the inclusion criteria. These cases were matched with the same number of patients according to age with a labial orthodontic treatment group. Pre- and post-treatment cephalometric radiographs were evaluated. Independent t test or Fisher exact tests were performed to assess the differences between the groups. Proclination of the upper incisors was higher in the labial group. Incisor mandibular plane angle (IMPA) showed an increase of 1.2° in the lingual group and 9.7° in the labial group. Lower incisor edge was approximately in a stable sagittal position in the lingual group but significant lower incisor proclination was seen in the labial group. The lower incisors were intruded (-1 mm) in the lingual group but lower incisors were minimally extruded (0.3 mm) in the labial group. No significant difference was found in the movements of upper and lower molars for both groups. The nature of lower incisor movement involved less protrusion in lingual orthodontics than the labial treatment. Lingual orthodontic treatment is a better option in adult cases where intrusion of lower incisors without labial tipping is desired.

Maxillary sagittal expansion in an adult patient

Relevance. Skeletal Class III malocclusion is known to be one of the most difficult malocclusions to correct. Nonsurgical treatment of Class III in adults is a challenge; however, this patient refused surgery. A treatment method with Fixed Anterior Growth Guidance Appliance (FAGGA) was investigated in the study.Materials and methods. This case report presents a 37-year-old woman with skeletal Class III malocclusion for maxillary deficiency. As the patient didn’t agree to surgery, she was treated by Fixed Anterior Growth Guidance Appliance, followed by 3D SMILE® clear aligners. Fixed Anterior Growth Guidance Appliance was used initially. After 4 months, the appliance was removed and clear aligner treatment was initiated. Post-treatment radiographs showed improvement.Results. Intraorally, in the upper arch, a total of 4.00 mm of space were gained (about 2.00mm distal to each canine). The post-treatment cephalometric analysis showed a skeletal A-P Class I, the Upper incisor inclination to the optic plane was not significantly altered, ANS — antArc was improved by 1.5mm, the Effective Length of the Premaxilla increased by 2.6mm, U1 — ANS’ decreased by 1.7mm, Incisor mandibular plane angle (IMPA) autonomously improved by 11 degrees.Conclusions. Maxillary deficiency was corrected successfully with the Fixed Anterior Growth Guidance Appliance. The treatment is being continued by 3D SMILE® clear aligners. The goal was achieved despite the patient’s age and nonsurgical treatment.