Dental Midline Deviation Research Articles

An Innovative Miniscrew-Based Jig for Unilateral Total Arch Mesialization

To describe the management of a case with skewed dental arches and midlines deviation using a novel approach based on temporary anchorage devices (TADs) to derogate the deviated arches by unilateral total arch mesialization. This study presents the treatment course of a 25-year-old man undergone a previous improper orthodontic treatment with unnecessary extraction of the upper and lower right first premolar teeth leading to asymmetric dental arches. The patient complained of dental crowding, an unaesthetic smile arch, and the maxillary and mandibular dental midline deviation. The proposed treatment plan goals were decrowding and correction of both arches asymmetry and achievement of coincident upper and lower dental midlines. The corrective treatment plan consisted of total arch mesialzation in both dental arches using an innovative TAD assisted jig. The overall treatment was accomplished in 28 months with significant improvement in facial aesthetic and reasonable periodontal status. This innovative clinical biomechanical setup of miniscrew-anchored sliding jig helped us achieve all the treatment goals (total dental arches mesialization, dental midline deviation correction, and ideal final aesthetic and occlusion) in a reasonable period of time. With proper planning, innovative designs based on TADs are effective alternatives in challenging cases such as uni or bilateral dental arches mesialization, and dental asymmetry correction.

Temporary Anchorage Device as an Innovative Alternative for Unilateral Arch Mesialization in Medical Application

Like any other medical intervention, orthodontic treatment has, in addition to its benefits, also associated risks and complications that are sometimes caused by wrongful treatment objectives. Correction of previous orthodontic malpractice is always a challenging problem in orthodontics. The present study aimed to introduce an innovative approach for total arch mesialization. In this study, the treatment course of a 25-year-old woman dissatisfied with her previous improper orthodontic treatment plan and unnecessary extraction of the upper and lower right first premolar teeth. Maxillary and mandibular dental midline deviation was evident concurrent with asymmetric dental arches and excessive gingival display a smile. The proposed corrective treatment plan consisted of right side temporary anchorage devices assisted total arch mesialization in both maxilla and mandible, followed by orthognathic surgery at the end. The patient’s final occlusion and facial profile improved significantly after the second treatment. The result was determined to be stable over a 1-year period. No significant evidence of root resorption was detected. Overbite decreased from 95% to 25%. Yaw correction was completely accomplished, and the final lateral cephalometric analysis after orthognathic surgery showed skeletal cl I relationship, normal proclination of upper and lower incisor teeth, and no evidence of periodontal complication and loss of vitality in the mandibular and maxillary teeth. The unilateral mesialization approach used in the current study prevented invasive therapies such as dental implants employing a special approach, which is less aggressive and more durable for the patient and revealed successful results with minimum side effects.

Differences in dental arch characteristics between genders in patients with suspected condylar hyperplasia in a North Sumatra subpopulation: a cross-sectional study

Background: Condylar Hyperplasia (CH) is a self-limiting mandibular condyle disorder that shows asymmetry progress in conjunction with associated occlusal changes as long as condylar growth is still active and leads to facial asymmetry. This study aimed to analysis the difference of dental arch characteristics based on genders in orthodontic patients with suspected CH in a North Sumatra subpopulation. Methods: This is a retrospective study of suspected CH patient’s clinical records who sought for the initial orthodontic treatment between January 2015 to March 2019. Patient with facial asymmetry (based on photography, posterior crossbite and midline deviation), the positive temporomandibular joint disorder in functional analysis, and no history of facial trauma were included in the study. Dental arch asymmetry was based on the measurement of dental midline deviation, canine tip in the dental arch, the distance of the upper canines from the palatal suture, and inter canine distance. The evaluation of dental arch was achieved by comparing arch width and length. Results: There was a significant difference (p<0.05) of upper canine distance from the palatal suture in female patients when evaluating upper dental arch asymmetry. There was a moderate correlation (r=0.379) in midline deviation between upper and lower dental arch. The dimension and dental arch form were mid and flat, and there was moderate correlation (r=0.448) between the upper and lower dental arch form in these suspected CH patients. Conclusion: Indeed skeletal asymmetry, the evaluation of the dental arch characteristic symmetry and arch form showed asymmetric occlusal characteristics in orthodontics patient with suspected CH in the North Sumatera subpopulation. In treating these patients, we recommend the plaster cast evaluation as essential and routine procedure in order to understand the complexity of occlusal change due to active growth of condylar and limitation in radiography evaluation.

Differences in dental arch characteristics between genders in patients with suspected condylar hyperplasia in a North Sumatra subpopulation: a cross-sectional study

Background: Condylar Hyperplasia (CH) is a self-limiting mandibular condyle disorder that shows asymmetry progress in conjunction with associated occlusal changes as long as condylar growth is still active and leads to facial asymmetry. This study aimed to analysis the difference of dental arch characteristics based on genders in orthodontic patients with suspected CH in a North Sumatra subpopulation. Methods: This is a retrospective study of suspected CH patient’s clinical records who sought for the initial orthodontic treatment between January 2015 to March 2019. Patient with facial asymmetry (based on photography, posterior crossbite and midline deviation), the positive temporomandibular joint disorder in functional analysis, and no history of facial trauma were included in the study. Dental arch asymmetry was based on the measurement of dental midline deviation, canine tip in the dental arch, the distance of the upper canines from the palatal suture, and inter canine distance. The evaluation of dental arch was achieved by comparing arch width and length. Results: There was a significant difference (p<0.05) of upper canine distance from the palatal suture in female patients when evaluating upper dental arch asymmetry. There was a moderate correlation (r=0.379) in midline deviation between upper and lower dental arch. The dimension and dental arch form were mid and flat, and there was moderate correlation (r=0.448) between the upper and lower dental arch form in these suspected CH patients. Conclusion: Indeed skeletal asymmetry, the evaluation of the dental arch characteristic symmetry and arch form showed asymmetric occlusal characteristics in orthodontics patient with suspected CH in the North Sumatera subpopulation. In treating these patients, we recommend the plaster cast evaluation as essential and routine procedure in order to understand the complexity of occlusal change due to active growth of condylar and limitation in radiography evaluation.

Evaluation of dental arches in orthodontic patients with condylar hyperplasia in a North Sumatra subpopulation: a cross-sectional study

Background: Condylar Hyperplasia (CH) is a self-limiting mandibular condyle disorder that shows asymmetry progress conjunction with associated occlusal changes as long as condylar growth is still active and leads to facial asymmetry. This study aimed to evaluate dental arches by analyzing dental arch asymmetry and form in orthodontic patients with CH in a North Sumatra subpopulation. Methods: This is a retrospective study of suspected CH patient’s clinical records who sought for the initial orthodontic treatment between January 2015 to March 2019. Patient with facial asymmetry (based on photography, posterior cross bite and midline deviation), positive temporomandibular joint disorder in functional analysis, and no history of facial trauma were included in the study. Dental arch asymmetry was based on the measurement of dental midline deviation, canine tip in the dental arch, distance of the upper canines from the palatal suture, and inter canine distance. The evaluation of dental arch was achieved by comparing arch width and length. Results: There was a significant difference (p&lt;0.05) of upper canine distance from the palatal suture in female patients when evaluating upper dental arch asymmetry. There was a moderate correlation (r=0.379) in midline deviation between upper and lower dental arch. The dimension and dental arch form was mid and flat, and there was moderate correlation (r=0.448) between the upper and lower dental arch form in these CH patients. Conclusion: The evaluation of dental arch symmetry and arch form showed asymmetric occlusal characteristics in orthodontics patient with CH in North Sumatera subpopulation. In treating these patients, we recommend the plaster cast evaluation as essential and routine procedure in order to understand the complexity of occlusal change due to active growth of condylar and limitation in radiography evaluation.

Evaluation of dental arches in orthodontic patients with condylar hyperplasia in a North Sumatra subpopulation: a cross-sectional study.

Background: Condylar Hyperplasia (CH) is a self-limiting mandibular condyle disorder that shows asymmetry progress conjunction with associated occlusal changes as long as condylar growth is still active and leads to facial asymmetry. This study aimed to evaluate dental arches by analyzing dental arch asymmetry and form in orthodontic patients with CH in a North Sumatra subpopulation. Methods: This is a retrospective study of suspected CH patient's clinical records who sought for the initial orthodontic treatment between January 2015 to March 2019. Patient with facial asymmetry (based on photography, posterior cross bite and midline deviation), positive temporomandibular joint disorder in functional analysis, and no history of facial trauma were included in the study. Dental arch asymmetry was based on the measurement of dental midline deviation, canine tip in the dental arch, distance of the upper canines from the palatal suture, and inter canine distance. The evaluation of dental arch was achieved by comparing arch width and length. Results: There was a significant difference (p<0.05) of upper canine distance from the palatal suture in female patients when evaluating upper dental arch asymmetry. There was a moderate correlation (r=0.379) in midline deviation between upper and lower dental arch. The dimension and dental arch form was mid and flat, and there was moderate correlation (r=0.448) between the upper and lower dental arch form in these CH patients. Conclusion: The evaluation of dental arch symmetry and arch form showed asymmetric occlusal characteristics in orthodontics patient with CH in North Sumatera subpopulation. In treating these patients, we recommend the plaster cast evaluation as essential and routine procedure in order to understand the complexity of occlusal change due to active growth of condylar and limitation in radiography evaluation.

Factors Affecting Total Treatment Time in Patients Treated with Orthognathic Surgery Using the Surgery-First Approach: Multivariable Analysis Using 3D CT and Scanned Dental Casts.

The aim of this study was to analyze factors affecting treatment times in patients treated with the surgery-first approach (SFA) for orthognathic surgery. Fifty skeletal class III patients who had undergone SFA bimaxillary orthognathic surgery were enrolled. Retrospective chart reviews and analysis of 3D CT and digitally scanned casts were conducted to assess the total treatment time. Statistical analysis was then performed with multiple study variables. Longer treatment times were required for patients with severe maxillary or mandibular teeth crowding (p = 0.009), a preoperative anterior open bite (p = 0.021), and those undergoing orthodontic extractions (p < 0.001). Longer treatment times were also observed when setting surgical occlusion in the postoperative anterior open bite (p = 0.007) and in patients with postoperative dental midline deviation (p < 0.001) and transverse maxillary deficiencies (p = 0.035). Treatment times were shorter when a class I molar key was formed in the surgical occlusion setup (p = 0.002) and in bilateral anterior and posterior occlusion with a minimum of four contact points (p < 0.001). The number of contact points, the number of extracted teeth, and postoperative midline deviation were identified as significant predictors. These results suggest that proper patient selection is important when considering SFA and that surgeons can reduce total treatment time with an appropriate surgical occlusion setup.

Without mini-plates, mini-implants and surgery: treatment of severe anterior open bite in an adult patient - a case report

Introduction: Currently, there is a tendency to treat open bite with mini-implants, miniplates, and orthognathic surgeries and build ups when these protocols are not always indicated and to be apply them unnecessarily and excessively. Objectives: This case report describes treatment of a severe anterior open bite in an adult patient with step bends and vertical elastics. Case report: The female patient was 29 years and 8 months old and reported that she had low self-esteem; therefore, she wanted to have her untreated open bite closed. By examination, a convex profile, vertical growth pattern, dental midline deviation, and tongue exposure could be seen upon smiling. The dental and skeletal sagittal relationship was Class II. The overjet was +5 mm and the anterior overbite was -5.5 mm. The severe skeletal open bite involved the first molars to the anterior teeth, and it was treated only with step bends and vertical elastics over 2 years. Results: Significant facial improvement, maxillary incisor exposure upon aesthetic smiling, and adequate overbite and overjet were observed. The upper and lower dental midlines fit to the sagittal line. A counterclockwise rotation of the mandible was observed. The severe skeletal open bite was treated. Conclusions: Severe skeletal open bite malocclusion treated with step bends and vertical elastics in adult patient demonstrated efficient, predictable and stable open bite correction.

WILLIAMS-BEUREN SYNDROME AND ORAL FINDINGS

Williams-Beuren syndrome (WBS; OMIM #194050) is a developmental disorder characterized by congenital heart disease, intellectual disability, dysmorphic facial features and ophthalmologic abnormalities. Virtually every organ and system can be affected in WBS as a result of haploinsufficiency. Most cases are sporadic, although familial cases with autosomal dominant inheritance have been reported. Oral abnormalities are also described in clinical manifestations of the disease. This study describes orofacial features in 17 patients with WBS. Patients with a confirmed molecular diagnosis of WBS were examined for oral abnormalities through clinical oral evaluations and panoramic radiography. Malocclusion, specifically with dental midline deviation, and high-arched palate were the most common oral findings. The present study contributes to the knowledge of orofacial manifestations in WBS. Since such patients with WBS may develop severe oral abnormalities, early detection and treatment can help to improve their quality of life.

Comparison of condylar morphology changes and position stability following unilateral and bilateral sagittal split mandibular ramus osteotomy in patients with mandibular prognathism

BackgroundUnilateral sagittal split ramus osteotomy (USSRO) is not widely used given the postoperative instability caused by the inevitable rotation of the mandibular segment during surgery. However, the influence of mandibular movement on the condylar morphology and position stability has not been completely explored. The aim of the study was to quantitatively evaluate the effect of USSRO on the condylar surface morphology changes and postoperative stability in patients with mandibular lateral prognathism and compare these findings with the classic bilateral sagittal split ramus osteotomy (BSSRO).Patients/methodsThis was a retrospective study involving 134 patients with mandibular lateral prognathism who received USSRO (n = 56) and BSSRO (n = 78) surgery. Here, cone beam computed tomography (CBCT) was performed before surgery (T0), immediately after surgery (T1), and 1 year postoperatively (T2). Differences of condylar sizes, condylar surface deviation, and mandibular positioning parameters (dental midline deviation, SNB, SN-MP) were calculated from T0 to T2. Comparisons were performed at the deviated side or nondeviated side of condyles between the USSRO and BSSRO groups. The relation between the dental midline deviation and condylar surface morphology changes from T0 to T2 were investigated.ResultsCondylar surface morphology changes at the deviated side of temporomandibular joint (TMJ) before and 1 year after the surgery were significantly different between the USSRO and BSSRO groups. The dental midline deviation was related to the changes of condylar volume, surface size and surface deviation at the deviated side of TMJ in patients following USSRO. No significant difference was noted between the USSRO and BSSRO groups for postoperative condylar surface morphology changes at the nondeviated side. In both groups, significant differences between T0 and T1 and no significant difference between T1 and T2 were noted for all of the mandibular positioning parameters.ConclusionsBoth BSSRO and USSRO exhibit favorable postoperative stability in the correction of mandibular prognathism. After USSRO surgery, condylar surface changes occurred at the deviated side of the TMJ, and the dental midline deviation was closely related to the changes of condylar surface morphology. USSRO represents a stable alternative for minor asymmetric mandibular prognathism correction with the advantages of reduced operating time and surgical trauma.

Quantification of maxillary dental midline deviation in 2D photographs: Methodology trial

Discrepancy of the upper dental midline to the facial midline plays an important role in smile aesthetic assessment. This study presents different reference points to quantify the deviation of upper dental midline to the facial midline in 2D frontal photographs. The aim was to find the most accurate, precise, and practical reference points to measure dental midline discrepancy in 2D photographs. A modified headset with a protractor was developed in order to achieve photographs in nine standardised head positions. Six reference points were used to detect the facial midline in the 2D photographs (eyebrows "EB", inner-canthus of the eyes "ICE", alae of the nose "AN", columella "C", nasolabial folds "NLF", and the philtrum "PH"). The deviation of the maxillary dental midline from the facial midline was measured and compared with clinical measurements. Standard deviations (SD), Root Mean Square Error (RMSE), Method of Moments' Estimator (MME), 2-way repeated measures ANOVA, and multi-level linear model were used to estimate the true errors. The different reference points responded significantly differently to changes in head position and all showed measurement errors, which increased with greater head rotation. Alae of the nose showed the least measurement error and the greatest precision in all head positions. The alae of the nose are the recommended reference points to identify the facial midline in order to quantify dental midline deviation from frontal photographs.

The Prevalence of Dental Midline Deviation in a Group of Orthodontic Patients

The study aimed to determine the prevalence of dental midline deviation in an orthodontic group of patients.The study was performed on 384 orthodontic patients (164 boys and 220 girls), between 6-23 years old. The data collected from orthodontic records were analysed according to the gender, age stages, environments areas, type of dentition and Angle Classes of malocclusions. All analyses were carried out using the SPSS. In the studied group the prevalence of dental midline deviation was 20.70%. The prevalence of dental midline deviation was increased in girls (12.24%), in patients over 12 years old (8.35%), from urban areas (14.32%), with mixed dentition (11.45%) and with Class I (11.20%) and II division 1 (6.25%) malocclusions. We founded statistically significant high correlations between dental midline deviation and age stages (p=0.028), type of dentition (p=0.001) and Angle classes of malocclusions (p=0.006). The dental midline deviation, commonly encountered in orthodontic practice, must be accurately diagnosed from the beginning of the treatment because the symmetry of the midlines is an essential criterion in achieving the aesthetic and functional objectives of the orthodontic treatment.

Maksiller Orta Hat Diastemasının ve Dental Orta Hat Sapmasının Farklı İskeletsel Maloklüzyonlar ile İlişkisinin Değerlendirilmesi

Maksiller Orta Hat Diastemasının ve Dental Orta Hat Sapmasının Farklı İskeletsel Maloklüzyonlar ile İlişkisinin Değerlendirilmesi

Maxillary dental midline deviation in the patient perspective

Objective: This study aimed to determine aesthetic perceptions of midline deviations by orthodontic patients; influence of adjacent structures to smile in the perception of deviations; and difference between patients treated in University and in private practice. Methods: In this observational comparative cross-sectionalstudy a smiling woman photograph was digitally modified, producing left maxillary dental midline deviations relative to facial midline. Twelve photographs were cropped in Group LCN including lips, chin and 2/3 of the nose; and group L including the lips. Non-parametric Friedman test ( = 0.05), followed by Wilcoxon test corrected by Bonferroni test ( = 0.0033) were used for multiple comparisons. Pearson correlation coefficient was used to study of the correlation and regression of the degree of smile esthetics on the midline deviations, adopting a significance level of 5%. Results: Patients were able to identify deviations from 2 mm. Among the groups of photos there was statistically significant difference in deviations of 2 and 3 mm. Comparing patients from University and private there was significant difference when comparing the photos in group LCN, without deviation and deviation of 2, 4 and 5 mm. Conclusions: Orthodontic patients are able to detect maxillary dental midline deviation from 2 mm. There was influence of viewing structures adjacent to smile in the perception of deviation for the private patients. University patients were more critical than private patients.

Three-dimensional evaluation of craniofacial characteristics related to mandibular asymmetries in skeletal Class I patients.

Our objective was to analyze the characteristics that affect skeletal Class I adults with mandibular asymmetries using cone-beam computerized tomography. The sample included cone-beam computerized tomography images of 120 subjects. Asymmetry was determined by the deviation of gnathion from the midsagittal plane and classified as relative symmetry, moderate asymmetry, or severe asymmetry. Maxillary and mandibular measurements were made, and the differences between the contralateral side and the deviated side were evaluated, as well as the differences between the categories of asymmetry. For patients with moderate asymmetry, there were significant differences between the contralateral and deviated sides for some measuments in the transverse and vertical planes. For those with severe asymmetry, statistically significant differences were found between the sides for all measurements, except for the measuments that evaluated the position of the mandibular condyle in the transverse and sagittal directions. Furthermore, a strong correlation was found in patients with severe asymmetry, between the deviation of the mandibular dental midline and the lateral displacement of gnathion. Patients with relative symmetry had a bilateral balance, whereas those with moderate and severe asymmetries showed several skeletal imbalances. A great deviation of the mandibular dental midline may indicate severe skeletal asymmetry in Class I adults.

Unilateral sagittal split ramus osteotomy: an alternative for some cases of asymmetric mandibular prognathism

The objective of this study was to propose a treatment protocol for patients with lateral prognathism based on the unilateral sagittal split ramus osteotomy (USSRO). This was a prospective study involving 31 patients with lateral prognathism, who required a bilateral sagittal split ramus osteotomy (BSSRO). Two groups were formed using the proposed protocol, with specific inclusion criteria for each group: BSSRO (n=17) and USSRO (n=14). Occlusal parameters (dental midline deviation, overbite, and overjet) were measured preoperatively (T0), at model surgery (T1), 1 month postoperative (T2), and 1year after surgery (T3) and compared. P-values of <0.05 were considered significant. No significant difference was found between the USSRO and BSSRO groups for all occlusal parameters (T0, T1, T2, and T3). In both groups, there was a significant difference between T0 and T1 and no significant difference between T1 and T2 or T1 and T3 in all of the occlusal parameters; the exception was overbite between T1 and T2 in the BSSRO group, which showed a significant difference. No patient in either group showed signs or symptoms of temporomandibular joint dysfunction at T0 or T3. USSRO was found to be a stable alternative in patients with asymmetric mandibular prognathism. At the same time, it reduced the operating time and morbidity when compared to BSSRO.

Craniofacial features affecting mandibular asymmetries in skeletal Class II patients.

The aim of this study was to evaluate the characteristics affecting different intensities of mandibular asymmetry in skeletal Class II adults using three-dimensional images. This study is clinically relevant since it allows professionals to evaluate the morphological components related to these deformities and more carefully obtain correct diagnosis and treatment plan for such patients. Cone-beam computed tomography data of 120 Class II patients (40 with relative symmetry, 40 with moderate asymmetry, and 40 with severe asymmetry) were imported to SimPlant Ortho Pro® 2.0 software (Dental Materialise, Leuven, Belgium). Three reference planes were established and linear measurements were performed from specific landmarks to these planes, comparing the deviated side and the contralateral side in each group, as well as the differences between groups. The correlation between midline mandibular asymmetry and other variables was also evaluated. Statistical analyses considered a significance level of 5%. Comparing the values obtained on the deviated side and on the contralateral side, there were significant differences for patients with moderate asymmetry and severe asymmetry. However, differences were seen more often in severe mandibular asymmetries. In those patients, there was a significant correlation of the gnathion deviation with lower dental midline deviation, difference in the lateral gonion positions, difference in the mandibular rami heights, and difference in the jugale vertical displacements. For skeletal Class II patients with mandibular asymmetry, some craniofacial features are related to chin deviation and require proper evaluation, including the bilateral differences in the ramus height, mandibular body length, transverse and vertical positioning of the gonion and jugale points.

Oral findings in Williams-Beuren syndrome.

BackgroundWilliams-Beuren syndrome (WBS; OMIM #194050) is a developmental disorder characterized by congenital heart disease, intellectual disability, dysmorphic facial features and ophthalmologic abnormalities. Oral abnormalities are also described in clinical manifestations of the disease. This paper describes orofacial features in patients with WBS.Material and MethodsSeventeen patients with a confirmed molecular diagnosis of WBS were examined for oral abnormalities through clinical oral evaluations and panoramic radiography.ResultsMalocclusion, specifically with dental midline deviation, and high-arched palate were the most common findings.ConclusionsThe present results contribute to knowledge on the orofacial manifestations of WBS. Since such patients with WBS may develop severe oral abnormalities, early detection and treatment can help improve their quality of life. Key words:Congenital abnormalities, Orofacial features, Williams-Beuren syndrome.

Esthetic preferences of laypersons of different cultures and races with regard to smile attractiveness.

Culture and ethnicity are among the factors affecting esthetic judgment of individuals. This study aimed to assess the acceptability threshold of variations in four components of an esthetic smile namely vertical lip thickness, dental midline deviation, buccal corridor, and the golden ratio in maxillary lateral incisors display among laypersons of different races and cultures. Raters (n = 35 in each city) among laypersons of nine cities namely Istanbul, Isfahan, Tabriz, Tehran, Doha, Rome, Sydney, Chicago, and Yazd, were given a photo album containing 27 random images of an attractive female smile, digitally altered with regard to the four smile components. They scored each picture from 0 to 100 in terms of smile attractiveness. Data were analyzed using SPSS 13 and the acceptability threshold for each component was calculated in each city using the Spearman and Wilcoxon tests. P< 0.05 was considered statistically significant. No significant differences were noted with regard to the increased vertical lip thickness, and an acceptability threshold could not be determined for it. The acceptability thresholds for midline deviations, buccal corridor, and the golden ratio were different among different cities. One-millimeter increase in the displayed width of maxillary lateral incisors was more desirable than the golden ratio standard width. Culture and race may significantly affect the esthetic preference of individuals with regard to smile attractiveness.

Perception of midline deviations in smile esthetics by laypersons

ABSTRACTObjective: To evaluate the esthetic perception of upper dental midline deviation by laypersons and if adjacent structures influence their judgment. Methods:An album with 12 randomly distributed frontal view photographs of the smile of a woman with the midline digitally deviated was evaluated by 95 laypersons. The frontal view smiling photograph was modified to create from 1 mm to 5 mm deviations in the upper midline to the left side. The photographs were cropped in two different manners and divided into two groups of six photographs each: group LCN included the lips, chin, and two-thirds of the nose, and group L included the lips only. The laypersons performed the rate of each smile using a visual analog scale (VAS). Wilcoxon test, Student’s t-test and Mann-Whitney test were applied, adopting a 5% level of significance. Results: Laypersons were able to perceive midline deviations starting at 1 mm. Statistically significant results (p< 0.05) were found for all multiple comparisons of the values in photographs of group LCN and for almost all comparisons in photographs of group L. Comparisons between the photographs of groups LCN and L showed statistically significant values (p< 0.05) when the deviation was 1 mm. Conclusions:Laypersons were able to perceive the upper dental midline deviations of 1 mm, and above when the adjacent structures of the smiles were included. Deviations of 2 mm and above when the lips only were included. The visualization of structures adjacent to the smile demonstrated influence on the perception of midline deviation.