Optimal antero-posterior position of the maxillary central incisors and its relationship to the forehead in adult African American females

Analysis of maxillary teeth and soft tissue profiles among Tibetan and Han Chinese females with facial symmetry for orthodontic treatment planning

The evaluation of maxillary teeth and soft tissue profiles is a critical component of orthodontic diagnosis and treatment planning. This study aimed to evaluate the correlation between the sagittal position of maxillary anterior teeth and facial profile esthetics among Tibetan and Han Chinese adult females for optimizing orthodontic diagnosis and treatment planning. A total of 100 Tibetan Chinese and 100 Han Chinese adult females with good facial symmetry were recruited. The smiling facial profile images with the maxillary central incisors and forehead in full view were taken based totally on the same standard. The photo measurement and head position were adjusted using the picture-enhancing software. The reference traces associated with forehead inclinations were utilized to assess the anteroposterior (AP) positions of the maxillary central incisors. The results showed that a round forehead was the dominant forehead shape for Tibetan (93%) and Han (55%) Chinese females. In Tibetan females, 85% of the maxillary central incisors were found to be located between the forehead's anterior limit line (the Gall line) and the goal anterior limit line (the Fall line), with 15% located posterior to the Fall line. This distribution manifested a strong association with incisor position and forehead inclination (R2  = 0.742). In Han females, 83% of the maxillary central incisors were located between the Fall line and the Gall line, with 12% posterior to the Fall line and 5% anterior to the Gall line. The positions of the maxillary central incisors exhibited a strong relationship with forehead inclination (R2  = 0.827). The maxillary central incisors were close to the aesthetic line in both ethnic groups, while forehead inclinations were correlated with AP maxillary incisor position. These findings demonstrated that there was a close relationship between the incisor position of Tibetan and Han females with facial symmetry and the forehead FFA factor, indicating a reference in oral hard and soft tissues for optimizing orthodontic diagnosis and treatment planning in terms of facial contour.

Placing the maxilla in the most aesthetic sagittal position: validation of several reference lines in relation to the forehead shape

The ideal sagittal position of the maxilla is highly subjective in orthognathic surgical treatment planning. There is no consensus on an analysis to predict the ideal sagittal position of the maxilla. The objective of this study was to determine the preferred maxillary position in relation to the forehead shape, in the Southern Chinese population. The maxilla position of eight patients was simulated based on Steiner's analysis (SA), glabella vertical (GV), Andrews' Element II (AE2), and the Barcelona reference (BR). The simulations were then used in an electronic survey, where respondents ranked the images for each patient from to 1-4 (most to least attractive). A total of 128 responses were collected from dental professionals and laypersons. The most preferred to the least preferred simulation was as follows (mean rank scores for the male and female patients in parenthesis): BR (males 2.06; females 1.98), GV (males 2.11; females 2.21), SA (males 2.59; females 2.40), and AE2 (males 3.24; females 3.41). There was no significant difference in the results according to the sex, age group, or profession of the respondents. The Barcelona reference and glabella vertical are useful in predicting the ideal maxillary position in patients with a flat forehead, and the Barcelona reference is the most preferred in patients with a rounded forehead.

The Impact of Clinical and Craniofacial Changes on the Surgical Outcomes of Lateral Pharyngoplasty in the Treatment of Obstructive Sleep Apnea

Objective  To verify if maxillomandibular retrusion, obesity, and increased neck circumference are factors of worse surgical prognosis for lateral pharyngoplasty in apneic patients. Materials and Methods  We evaluated 53 patients with obstructive sleep apnea who underwent lateral pharyngoplasty. Clinical evaluation was performed before the surgical procedure and included the measurement of body mass index (BMI) in kg/m 2 , neck circumference in centimeters, and a clinical evaluation of the facial profile obtained through the natural position of the oriented head. The polysomnographic evaluation was performed with at a minimum of 6 months after surgery, and polysomnographic results were correlated with the preoperative clinical data. Results  The mean age of the patients was 38.8 years; the mean BMI was of 29.28kg/m 2 , and 84.9% of the sample was composed of men and 15.1% of women. There was a significant reduction in the mean value of the main respiratory parameters verified by polysomnography, such as apnea-hypopnea index (AHI) from 31.60 events per hour to 8.15 ( p  < 0.001); NadirO 2 went from 81% to 85% ( p  = 0.002) and mean oxyhemoglobin saturation from 94% to 95% ( p  = 0.024). It was also observed that the greater the maxillomandibular retrusion, the lower the mean reduction of the AHI after surgery. The increase in neck circumference proved to be a factor associated with the surgical outcome, and for each 1-cm decrease in the neck circumference, the chance of surgical success increased 1.2-fold. Conclusion  Lateral pharyngoplasty is an efficient surgical obstructive sleep apnea treatment. The lower the neck circumference measurement, the greater the chances of surgical success, and clinically evaluated maxillomandibular retrusion can reduce the magnitude of improvement in respiratory parameters after lateral pharyngoplasty in apneic patients.

Sagittal Position of the Upper Incisor in Relation to the Forehead in Peruvian Individuals with Different Skeletal Relationships

AIM

The aim of this study was to determine the sagittal position of the upper incisor considering Andrews' analysis based on the position of the forehead in Peruvian individuals with different skeletal relationships.

MATERIALS AND METHODS

This retrospective, cross-sectional study included 212 lateral head radiographs of Peruvian individuals (males: 85, mean age 21.38 ± 6.88, and females: 127, mean age 21.18 ± 6.95), with different skeletal relationships (Class I group = 96, Class II group = 57, Class III group = 59). The values of the ANB, SNA, SNB angles as well as the forehead anterior limit line (FALL) and goal anterior limit line (GALL) points were identified in the radiographs, and then a vertical line was drawn in each point to determine if the upper incisor was positioned forward (protruded), backward (retruded) or within (adequate) these lines. Two trained and calibrated investigators performed all the measurements. The Chi-square test was used to evaluate associations. A p-value < 0.05 was considered statistically significant.

RESULTS

Overall, the sagittal position of the upper incisor showed a significant association with the sagittal skeletal relationship (p = 0.001). The upper incisors showed an adequate position (41.7%), protruded position (56.10%), and retruded position (42.40%), for Class I, II, and III skeletal relationships, respectively, as highest percentages in each Class. Statistical significance was found for females only (p = 0.005).

CONCLUSION

Skeletal Class I mainly showed an adequate position of the upper central incisor, whereas for Class II a protruded position was most frequently found, and Class III presented a retruded position.

CLINICAL SIGNIFICANCE

Andrews' analysis based on the position of the forehead in Peruvian individuals is a valuable tool for orthodontic diagnosis. How to cite this article: Bazán-Mendoza JR, Arias-Modesto PB, Ruíz-Mora GA, et al. Sagittal Position of the Upper Incisor in Relation to the Forehead in Peruvian Individuals with Different Skeletal Relationships. J Contemp Dent Pract 2023;24(11):821-825.

Evaluation of optimal anterior-posterior position of upper incisors through ANS point: a retrospective study on a Chinese sample

OBJECTIVES

This study was designed to determine the optimal anterior-posterior (AP) position of upper incisors through Anterior Nasal Spine (ANS) point.

MATERIALS AND METHODS

Lateral cephalometric radiographic images of 690 patients were collected and divided into a derivation group and a validation group, and the former were subdivided into a proper AP position (PAP) group and an improper AP position (iPAP) group. The distance from facia-axis (FA) point of upper incisors to the line perpendicular to Frankfort horizontal (FH) plane through ANS (FA-ANS) was measured, and the relationship between FA-ANS and several cephalometric indices were studied through Pearson correlation analysis. Receiver operating characteristic (ROC) curves for different clinical indices were analyzed to evaluate the diagnostic efficiency of optimal AP position of upper incisors.

RESULTS

The average value of FA-ANS in PAP group was 0.57±1.99, which was significantly different from FA-ANS in iPAP group. Cephalometric indices such as U1-NA, U1-SN, AB-NPo, UL-TVL, Wits, and ANB were found to be correlated with FA-ANS. The receiver operating characteristic (ROC) curves represented a greater diagnostic efficiency of FA-ANS compared with other clinical indices.

CONCLUSIONS

ANS point, as a stable skeletal landmark, could be used to access an optimal AP position of upper incisors, providing aids to clinical diagnosis and treatment goal determination for clinical practice.

CLINICAL RELEVANCE

A new index FA-ANS, together with other traditional indices, could help determine the optimal position of upper incisors and provide a personalized therapeutic plan.

Anteroposterior relationship of the maxillary central incisors to the forehead in adult Chinese females

Objectives:

The objectives of the study were to evaluate the anteroposterior (AP) relationship of the maxillary central incisors to the forehead in adult Chinese females.

Material and Methods:

The study sample consisted of 100 lateral smiling photographic images of adult Chinese females who were seeking orthodontic treatment (mean age = 24.0 + 6.5 years old). The study sample was compared to a control sample consisting of 100 images of adult Chinese females with harmonious facial profiles downloaded from the internet. The images were resized and rotated to the upright head position in an image editing software. Reference lines were constructed to evaluate forehead inclinations and AP positions of the maxillary central incisors.

Results:

In the control sample, 80% of the maxillary central incisors were positioned between the facial axis point of the forehead (FFA) and the glabella. About 13% were positioned posterior to the FFA point and 7% anterior to the glabella. In the study sample, 31% of the maxillary central incisors were positioned between the FFA point and glabella, 52% posterior to the FFA point, and 18% anterior to the glabella. There was a strong correlation between the position of the maxillary central incisors and forehead inclination in the control sample (r2 = 0.827). The difference in AP maxillary central incisor position relative to the forehead between the two groups was found to be statistically significant (P = 0.000).

Conclusion:

The forehead may be an important landmark when evaluating the AP position of maxillary incisors in adult Chinese female patients.

Patterns of Facial Profile Preference in a Large Sample of Dental Students: A Cross-Sectional Study

The objective of this study was to explore dental students’ facial profile preferences in a large sample of students. Nine hundred and nineteen dental students of four dental schools were involved. As part of a larger study on dentofacial esthetics, six photo series consisting of one unaltered and four altered variants of the same female profile were distributed among the students. The altered features were ones that are esthetically significant according to the literature. The students had to indicate the photo in each series that they preferred. The data were analyzed in a regression model in which preference in the given photo series was the dependent variable and gender, grade of studies, and dental school were the factors. Eight hundred and sixty-one students (93.7%) responded. Gender and dental school were not associated with the observed preferences, but the grade of studies was associated for three of the modified parameters: chin prominence, the sagittal position of the maxillary dental arch, and the simultaneous modification of the prominence of the chin and the nose. This study has confirmed several earlier observations, and new observations have also been made. We have demonstrated that the anteroposterior position of the maxillary incisors may be an important determinant of profile esthetics, even if this position does not influence the situation of the soft tissues and if the forehead cannot be used as a reference. We have also shown that the harmony between the nose and the chin overrides the importance of their individual dimensions.

Relationship of anteroposterior position of maxillary central incisors with the forehead in an adult Iranian subpopulation: A cross-sectional study

OBJECTIVE

This study aimed to assess the relationship of the anteroposterior position of maxillary central incisors with the forehead in an Iranian subpopulation residing in Kermanshah city.

MATERIALS AND METHODS

In this cross-sectional study, 12 orthodontists were requested to analyse full-smile profile photographs with complete maxillary incisor and forehead show in 70 patients with optimal facial harmony (35 males and 35 females) as the control group and 140 patients without optimal facial harmony (70 males and 70 females) as the test group. The inclusion criteria were (I) males and females between 18-60 years seeking orthodontic treatment and (II) willingness for participation in the study. The exclusion criteria were (I) presence of severe craniofacial anomalies, and (II) history of orthodontic treatment. The photographs were traced and analysed using Digimizer Image Analysis software 5.3.5. Data were analysed using STATA version 14.2 via independent t-test and linear regression.

RESULTS

A significant difference existed in the anteroposterior position of maxillary incisors in males between the test and control groups (P=0.002). However, this difference was not significant in females of the two groups (P=0.77). A significant difference was noted in the anteroposterior position of maxillary incisors between males and females in the test group (P=0.001) but not in the control group (P=0.80). The frontal angle had a significant correlation with gender and anteroposterior position of maxillary incisors in both groups (P<0.001).

CONCLUSIONS

According to the results, the anteroposterior position of maxillary incisors was significantly different in the test and control groups. The maxillary incisors in males were more retruded than in females. Also, the frontal angle had a significant correlation with the anteroposterior position of maxillary incisors, and by 1° increase in the frontal angle, the incisors were protruded by averagely 0.307mm.

A Novel Device to Measure the Optimal Position of Central Incisors in Anteroposterior Dimension Clinically: “P” Device

Facial esthetic has always been a concern for humans for ages. The anteroposterior (AP) position of central incisors plays a key role in building facial esthetic in a smiling profile view. There have been various cephalometric, profilometric, and photographic methods used in the past to assess and predict the AP position of maxillary incisors in their optimal esthetic position. Our new device will help to predict, assess, and measure the optimal AP position of maxillary central incisors clinically using the glabella as a landmark.

Sagittal Relationship between the Maxillary Central Incisors and the Forehead in Digital Twins of Korean Adult Females

OBJECTIVE

Digital twins of adult Korean females were created as a tool to evaluate and compare the sagittal relationship between the maxillary central incisors and the forehead before and after orthodontic treatment.

METHODS

Digital twins were reconstructed for a total of 50 adult female patients using facial scans and cone-beam computed tomography (CBCT) images. The anteroposterior position of the maxillary central incisor and the forehead inclination were measured.

RESULTS

The control group presented a mean of 6.7 mm for the sagittal position and 17.5° for forehead inclination. The study group showed a mean of 9.3 mm for the sagittal position and 13.6° for forehead inclination. Most Korean females seeking orthodontic treatment had their maxillary central incisor anterior to the glabella. In contrast, fewer Korean females who completed their orthodontic treatments had their maxillary central incisor anterior to the glabella. Furthermore, patients who had completed the orthodontic treatment were more likely to have the maxillary central incisor between the forehead facial axis and glabella.

CONCLUSION

The use of digital twins for three-dimensional (3D) analysis of the profile implies a high clinical significance. In addition, as the facial profile of Koreans is different from that of Caucasians, careful consideration should be made when setting treatment goals for the anteroposterior position of the maxillary central incisors.

Selected Orthodontic Principles for Management of Cranio-Maxillofacial Deformities

An understanding of fundamental orthodontic principles involving diagnosis, treatment planning, and clinical strategies is essential for achieving successful outcomes in the treatment of craniofacial patients, particularly cleft lip/palate. This article focuses on: customizing a mandibular dental arch form using the WALA ridge; accurately diagnosing the maxillary skeletal transverse dimension (cusp to cusp/fossa to fossa); coordinating the upper dental arch with the lower; using a smiling profile and glabella vertical to assess anteroposterior jaw position; and leveling the mandibular curve of Spee while considering the lower one-third of the face. These concepts influence treatment outcomes to the extent they are used.

Facial Versus Skeletal Landmarks for Anterior-Posterior Diagnosis in Orthognathic Surgery and Orthodontics: Are They the Same?

PURPOSE

The purpose of this investigation was to evaluate diagnostic agreement in anterior-posterior (AP) categorization of the maxilla and mandible between a skeletal-landmark analysis and a facial-landmark analysis for treatment planning of orthognathic surgery and orthodontics.

MATERIALS AND METHODS

This retrospective, consecutive case series of adult patients who presented to the Mayo Clinic orthodontic department compared maxillary and mandibular AP diagnoses. Steiner's analysis of the sella-nasion-A point angle and sella-nasion-B point angle was used for a skeletal-landmark diagnosis. Element II of Andrews' 6 elements of orofacial harmony was used for a facial-landmark diagnosis. Both diagnoses were categorized as either deficient, optimal, or excessive for each jaw. Categorization of the skeletal landmark was determined by normative data, whereas the facial landmark provides a customized categorization unique to each individual.

RESULTS

Weighted κ statistics were completed to test agreement between the categories determined by the skeletal and facial landmarks. The maxilla showed poor agreement, and the mandible showed slight agreement.

CONCLUSIONS

No agreement was found for AP categorization of the maxilla and mandible between skeletal-landmark and facial-landmark analyses. Most mandibles were diagnosed as retrognathic by the facial landmark, whereas most were diagnosed as optimal by the skeletal landmark. When the 2 landmarks disagreed, the facial landmark defined the optimal position farther anterior. The landmark chosen for diagnosis will impact the optimal jaw position and can affect orthognathic and orthodontic outcomes.