The ability of orthodontists and laypeople to discriminate mandibular stepwise advancements in a Class II retrognathic mandible

Mandibular advancement analysis among orthodontists, lay people and patients in class II malocclusion subjects. A three-dimensional imaging study

OBJECTIVE

To evaluate the acceptance of orthodontists, laypeople and the patient when progressive mandibular advancements are performed in class II subjects with mandibular retrognathism.

SETTING AND SAMPLE

3D images were obtained by an optical surface scanning of fifteen individuals (12 males and three females, mean age of 23 years and 8 months) with mandibular retrognathism in three mandibular positions: maximum intercuspation (MIC) and progressive mandibular advancement of 2 and 4 mm.

METHODS

The images (n = 45) were evaluated through a scale by two groups of panellist, 20 orthodontists, 20 laypeople and by the patients themselves (n = 15). The participants evaluated and rated each video and give scores between 0 and 10, according to their perception of facial harmony. MANOVA for repeated measures was used for intra- and intergroup differences and to evaluate the patients' self-perception.

RESULTS

Laypeople reported better face acceptance than orthodontists in MIC and progressive mandibular advancement of 2 and 4 mm (P < .0001). 80% of the patients evaluated their own face as pleasant in MIC. Around half of them did not note significant difference following mandibular advancement of 2 mm as compared with MIC and even two-third attributed lower scores when the mandible was advanced 4 mm.

CONCLUSION

A high variability was observed among all groups of raters. Patient´s opinion should be taken into account when mandibular advancement of 4 mm or more is planned. This study suggests that a thorough discussion of facial changes resulting from mandibular advancement should be carried out among professionals, parents and patients.

Changes in the craniofacial structures and esthetic perceptions of soft-tissue profile alterations after distalization and Herbst appliance treatment

INTRODUCTION

The purpose of this prospective clinical trial is to evaluate the changes of soft tissues and designate the esthetic perceptions of children with Class II malocclusion after Herbst appliance therapy and maxillary molar distalization using stereophotogrammetry.

METHODS

Thirty patients were allocated either to Herbst (6 boys and 9 girls; mean age = 11.60 ± 0.82 years) or distalization (4 boys and 11 girls; mean age = 11.46 ± 1.30 years) groups. Dentoskeletal and soft-tissue treatment changes were examined objectively by cephalometric analysis and stereophotogrammetry, respectively. Pre- and posttreatment profile views were evaluated subjectively by orthodontists and laypeople using the 7-point Likert scale. Intra- and intergroup comparisons for the repeated measurements were performed with 2-way variance analysis. Bonferroni test was used for multiple comparisons (P ≤0.05).

RESULTS

Greater skeletal changes were observed in the Herbst group than in the distalization group. Maxillary incisor retrusion and mandibular incisor protrusion were observed in the distalization and Herbst groups, respectively. Stereophotogrammetric measurements showed that mandibular body length and lower and anterior facial height increased in both treatment groups. Convexity angle (P = 0.020) and labiomental angle (P = 0.033) were greater in the Herbst group than the distalization group.

CONCLUSIONS

The skeletal contribution to correction of maxillomandibular discrepancy was greater in the Herbst group than the distalization group. Significant profile improvements were recorded for both groups with treatment. After both treatments, orthodontists were found to have higher rates of detection in the profiles than laypeople. The esthetic contribution of treatments to the facial profile was found similar in both groups.

Self-perception of facial esthetics by patients with different profiles compared with assessments of orthodontists and lay people

INTRODUCTION

This study evaluated the perception of facial esthetics of patients with different profiles as assessed by orthodontists, lay people, and patients.

METHODS

The sample comprised 120 patients (81 females, 39 males; mean age, 26.3 years) selected from private practices at the onset of orthodontic treatment. The patients were divided into 3 groups of 40 according to the type of facial profile. The groups were composed of straight, concave, and convex profiles, on the basis of the facial convexity angle (G.Sn.Pog') measured on the initial cephalometric tracings. Patients analyzed only their frontal (smiling and at rest) and profile facial photographs and evaluated the pleasantness of these images on a 5-point Likert scale. A group of 30 orthodontists and 30 lay people also evaluated the patients' facial pleasantness, using the same scale. Factorial analysis of variance (convexity and sex) was used to evaluate the differences between the convexities, and analysis of variance mixed model (type of evaluator and sex) to compare the 3 categories of evaluators, using the aligned rank transform technique. The correlation between the convexity angle and facial pleasantness was assessed by the Spearman correlation coefficient.

RESULTS

Patients and lay people assigned higher pleasantness scores than orthodontists, with statistically significant differences for all evaluations, except for the frontal analysis of the convex group. The correlation coefficients regarding profile convexity and facial pleasantness were negative, indicating a tendency that more convex or concave facial profiles received lower pleasantness scores; however, this correlation was only significant in the evaluation of profile photographs by orthodontists.

CONCLUSIONS

Patients with different profiles were scored with acceptable faces by lay people and patients themselves. Orthodontists' perceptions were different; they attributed lower pleasantness scores. Discrepant profiles affect facial esthetics in the profile view when judged by orthodontists.

Thresholds of Abnormality Perception in Facial Esthetics among Laypersons and Dental Professionals: Profile Esthetics

Aim. To find thresholds at which laypersons and dental professionals from Jordanian population perceive abnormalities in sagittal positioning of upper and lower jaws as a major determinant to facial profile esthetics. Materials and Methods. Using photo editing software, a baseline profile image of a young male was manipulated on a 2 mm incremental basis to move each of the upper and lower jaws backward and forward relative to true vertical line (TVL) at which four variables of maxillary and mandibular retrusion and protrusion were researched. A total of 120 participants divided equally into four groups of laypersons, general dental practitioners (GDPs), orthodontists, and oral and maxillofacial surgeons (OMFSs) rated the images using an analog scale of 100 mm long. The image that showed the first statistical difference compared to the baseline was considered as a threshold of abnormality. Results. Laypersons, GDPs, and OMFSs perceived the abnormality in the maxillary retrusion at −5 mm to TVL, while orthodontists defined that at −3 mm. All dental professionals perceived the abnormality in the maxillary protrusion at +1 mm to TVL while the layperson group at +3 mm. A threshold of −7 mm mandibular retrusion to TVL was abnormally perceived by all groups. All dental professionals realized the abnormality in the mandibular protrusion at 0 mm to TVL while the laypersons at +2 mm. Conclusion. These thresholds regarding profile esthetics may contribute to the process of establishing proper orthodontic treatment planning that suits the highest facial esthetic standards.

Esthetic perception of facial profile changes in Class II patients treated with Herbst or Forsus appliances

OBJECTIVE

To evaluate the esthetic perceptions of orthodontists and laypersons for facial profile changes after orthodontic treatment using Herbst or Forsus appliances.

MATERIALS AND METHODS

Pre- and posttreatment facial profile contour images of 20 Class II patients treated with Herbst (group H; n = 10) and Forsus (group F; n = 10) appliances were analyzed by 30 orthodontists and 30 laypersons, who graded them from 1 (unattractive) to 10 (very attractive) using a visual analog scale. Two assessments were carried out with a 15 day-interval. In the first evaluation, 40 images were presented in a random sequence. In the second evaluation, initial and final facial profile images of each patient were randomly presented side by side. To compare groups in relation to treatment method, Mann-Whitney tests were used. To evaluate differences between time points, Wilcoxon tests were used.

RESULTS

In the first evaluation, there was a significant difference between initial and final images only for group H, for both laypersons (P = .017) and orthodontists (P = .037). There was also a significant difference between laypersons and orthodontists in their ratings of posttreatment Herbst appliance profiles (P = .028). There was no significant difference between initial and final facial profile images for group F and no significant differences between or within evaluator groups in their ratings of initial or final Forsus appliance profiles. In the second evaluation, there was a significant difference between appliance groups only for laypersons, who considered cases treated with the Herbst appliance more attractive than those treated with the Forsus (P = .031). Laypersons also considered Herbst profiles more attractive than did orthodontists (P = .047).

CONCLUSIONS

Class II malocclusion treatment using the Herbst appliance may produce a more esthetically improved facial profile silhouette compared with Forsus appliances. The magnitude of perceived changes may not be considered clinically relevant.

Esthetic perception of facial profile changes after extraction and nonextraction Class II treatment

This retrospective study evaluated facial profile pleasantness determined by two protocols of Class II treatment. The sample comprised facial profile silhouettes obtained retrospectively from the pretreatment (T1) and posttreatment (T2) cephalograms of 60 patients (42 males and 18 females) divided into two groups. One group of 30 patients (mean age of 12.84 years) was treated with the extraction of maxillary first premolars (mean treatment time of 2.7 years), and the other group of 30 patients (mean age of 12.81 years) was treated with a mandibular advancement appliance (Forsus) (mean treatment time of 2.49 years). The facial profile silhouettes (T1 and T2) were randomly distributed in an album containing one patient per sheet. The examiners consisted of 60 orthodontists and 60 lay individuals, who analyzed the profiles in regard to facial pleasantness, using the Likert scale. A comparison between stages T1 and T2 of the two treatment protocols and between the examiners was performed by mixed-design analysis of variance at a significance level of 5%. The results demonstrated a significant difference between T1 and T2 (greater scores for T2 compared to T1), and between lay individuals and orthodontists (orthodontists assigned higher scores), but with no significant difference between the treatment protocols. Both protocols produced positive effects on the facial profile esthetics, from the standpoint of lay individuals and orthodontists.

Effect of facial profile convexity on the perception of mandibular asymmetry using three-dimensional stereophotogrammetric images

OBJECTIVE

The aim of this study was to test the hypothesis that sagittal anomalies have an effect on the perception of mandibular asymmetry. Secondly, it aimed to determine the asymmetry perception threshold of orthodontist and laypeople.

SETTING AND SAMPLE POPULATION

A total of 90 individuals were included in the study from different professions (Orthodontist: n:45, layperson: n:45).

MATERIALS & METHODS

The reference image was obtained with 3dMD device and selected from among the individuals with class I soft tissue relationship. In the sagittal direction, the chin area has been moved as to produce 5 and 10 degrees of change in facial convexity angle. Similarly, 0, 2, 4, 6, 8 and 10 mm changes were made and recorded in video format. Manipulated images were scored by participants with VAS method.

RESULTS

When differences between the groups were evaluated, the reference image was scored similarly by orthodontists and layperson (P: .017). No statistically significant difference was observed between the groups in other parameters (P > .05). Asymmetry in 0-2 mm range was evaluated by orthodontist and layperson and statistically insignificant (P > .05). Similarly, the change between 8 mm and 10 mm was different in both groups and statistically insignificant (P > .05). Also, when there was no asymmetry, the sagittal direction was differently scored by the participants in both groups and statistically insignificant (P > .05).

CONCLUSIONS

It was observed that the effect of sagittal direction changes on asymmetry perception was not statistically significant.

Mandibular Protraction Appliance Effects in Class II Malocclusion in Children, Adolescents and Young Adults

The aim of this study was to evaluate the effects of the mandibular protraction appliance (MPA) for treating mild to moderate Class II malocclusion at different stages of dentofacial development. Lateral radiographs were evaluated before (T0) and at the end (T1) of orthodontic treatment with fixed appliance associated with MPA. Sixty-five consecutively treated patients were divided according to the stage of dentofacial development: 21 children in late mixed dentition, 22 adolescents and 22 young adults with full permanent dentition. The differences between and within groups were analyzed by MANOVA at p<0.05. The correction of anteroposterior discrepancy (Wits) was significantly reduced in all development stages (p<0.01), with no difference between groups. Class II was corrected predominantly by dental changes in the mandibular arch, with accentuated proclination of the mandibular incisors and mesial displacement of mandibular molars. The MPA had no skeletal effects in any of the groups, except for a mild reduction of SNA (p=0.018) and ANB angles (p<0.0001) among the mixed dentition children. With regard to soft-tissue profile, facial convexity decreased significantly in all groups (p<0.01). In conclusion, the MPA associated with fixed appliance corrected the Class II occlusion, basically by a mandibular arch protrusion. A mild skeletal maxillary change was significant only when this treatment protocol began during mixed dentition.

Factors influencing orthodontic treatment time for non-surgical Class III malocclusion

Objective:

To identify variables and their effect size on orthodontic treatment time of Class III malocclusion.

Material and Methods:

Forty-five Class III malocclusion cases were selected from 2008 patients' records. Clinical charts, cephalometric radiographs, and pre and posttreatment dental casts were evaluated. Age, sex, PAR index at T1 and T2, overjet, missing teeth, extractions, number of treatment phases, missed appointments, appliance breakages, and cephalometric variables SNA, SNB, ANB, Wits, SnGoGn, CoA, CoGn, IMPA, 1.PP were investigated by multiple linear regression analysis and stepwise method at p<0.05. The sample was also divided into two groups: Group 0-2 (patients who had missed two clinical appointments or less) and Group >2 (patients who missed more than 2 appointments), to detect the influence of this data on treatment time and the quality of the treatment (PAR T2).

Results:

Average treatment time was 30.27 months. Multiple regression analysis showed that missed appointment (R2=0.4345) and appliance breakages (R2=0.0596) are the only variables able to significantly predict treatment duration. Treatment time for patients who missed more than 2 appointments was nearly one year longer. However, no significant influence on PAR T2 was observed for those patients.

Conclusion:

Orthodontic treatment duration in Class III patients is mainly influenced by factors related to patient compliance. Patients who missed more appointments did not show worse orthodontic finishing, but longer treatment. No occlusal, cephalometric, or demographic variable obtained before treatment was able to give some significant prediction about treatment time in Class III patients.

True vertical validation in facial orthognathic surgery planning

Objectives: To validate the effectiveness of the original standards of True Vertical (TV) Subnasal Line in orthognatic surgery planning. The present study evaluates the changes occurring in patients with skeletal Class II alterations programmed for orthognathic surgery with a view to improving their facial profile. Study design: We showed a series of black profiles (composed by a first control group of subjects with normal occlusion, and another two additional groups comprised patients before –Group 2- and after orthognatic surgical correction of Class II malocclusion -Group 3-) for three groups of observers (orthodontists, surgeons and laypeople). The facial images became black silhouettes in order to determine a series of parameters (including aesthetic assessment) by means of the observers. Their observation were assessed using a 5-point Likert scale. Results: The sample was composed of 52 profile’s subjects who were tested for a total of 72 observers. Aesthetic assessment yielded mean scores of 2.57, 1.67 and 2.46 for groups 1, 2 and 3, respectively. There was a statistically significant difference (p<0.001) between group 1 versus group 2. There were no significant differences in terms of observer assessment of aesthetics, with the exception of a wider perception range among the orthodontists. Regarding the studied profile measures, significant differences were recorded for point B’ and Pg’ (p<0.02) between groups 2 and 3 (i.e., pre- versus post-surgery). Conclusions: The results of our study suggest the subnasale vertical and sagittal measures of the lower third of the face are decisive in facial aesthetics, and therefore also for the planning of orthognathic surgery. Consequently, these aesthetic parameters can be used as an objective tool for the planning of orthodontic treatment.

Key words:Facial profile, Class II, orthognathic surgery, cephalometric analysis, facial soft tissue, subnasale vertical.