Midline Discrepancy Research Articles

Tetris Genioplasty 2.0: The Evolution of the Technique.

The chin is a key feature in facial aesthetics, contributing essential projection to the profile. Proper alignment ensures facial harmony, while misalignments can create irregularities that may require surgical correction. Over time, various genioplasty techniques have been developed to address a broad range of asymmetries. Tetris Genioplasty is a novel osteotomy technique designed to improve cases where the skeletal midline does not align with the dental midline, delivering significant corrective results. Building on extensive experience with patients presenting this condition, this technical note introduces Tetris Genioplasty 2.0, a refined version of the original "Tetris" Osteotomy. This enhanced technique minimizes the presence of edges during bone segment realignment, resulting in a more seamless facial profile. This study aims to detail the advancements in the Tetris Genioplasty technique, demonstrating how the 2.0 modification offers an optimized approach to improving facial symmetry and aesthetic outcomes in complex midline discrepancies.

Exploring Midline Asymmetry: A Comprehensive Study Among Adolescents in the North Bihar Population

Objectives In the contemporary era, achieving a sense of equilibrium is a paramount concern, and a visually pleasing smile is intricately linked to both professional success and social acceptance. Esthetics, with a specific focus on Oro-facial aesthetics, emerges as a primary motivation for individuals seeking dental treatment. Nevertheless, there exists an optimal and aesthetically pleasing range of dental midline deviation. The current study aimed to ascertain the prevalence of dental midline shifting and the average extent of midline discrepancy among adolescents (aged 13-17) from North Bihar population. Material & Methods Two hundred subjects participated in the study, with 100 males and 100 females selected based on predetermined inclusion criteria. Intraoral frontal occlusion photographs were captured for each participant, and subsequent analysis was done utilizing Digimizer software. Statistical analysis was applied to the linear measurement data obtained through photographic evaluation. Results The study’s findings revealed a noteworthy proportion of subjects displaying deviations between upper and lower midlines and anterior teeth midlines, falling within the range of 0.03-3.80 mm. Conclusion The prevalence of these deviations was observed to be higher in males compared to females, and this difference was statistically significant.

The Impact of Radiation on Nipple Symmetry After Bilateral Nipple-Sparing Mastectomy and Implant-Based Reconstruction: An Objective Analysis.

Radiation therapy can adversely affect outcomes of implant-based breast reconstruction, potentially complicating procedures like nipple-sparing mastectomy (NSM), which is increasingly popular in breast cancer management. This study aims to evaluate the impact of radiation on nipple symmetry in patients undergoing bilateral NSM with implant-based reconstruction. We conducted a retrospective analysis using data from an Emory University review board-approved database. This encompassed bilateral NSMs coupled with immediate implant-based reconstructions. The BCCT.core software was employed to objectively measure nipple asymmetry preoperatively and postoperatively. Metrics, such as Breast Retraction Assessment values, upper nipple retraction, lower breast contour, and nipple to midline (NML) discrepancies were quantified. The study included 80 patients with a minimum of 1 year of follow-up; among them, 15 received radiation therapy (RT) while 65 did not. The reconstructions were divided into tissue expander, used in 39 cases (48.8%), and direct-to-implant (DTI), employed in 41 cases (51.2%). The DTIs were further categorized based on the location of the implant: 22 subpectoral and 19 prepectoral. Radiation was applied to 15 breasts, distributed among prepectoral DTI (4), subpectoral DTI (6), and tissue expander (5). Breast Retraction Assessment scores significantly differed between the nonirradiated and irradiated groups (1.49 vs 2.64, P < 0.0004). Nipple to midline differences and Upper Nipple Retraction also significantly varied postradiation, especially when comparing subpectoral and prepectoral implant placements. Radiation therapy has a detrimental effect on nipple symmetry after bilateral NSM and implant-based reconstruction, with variations seen regardless of the implant's placement or the reconstructive technique utilized. Specifically, subpectoral reconstructions irradiated were prone to lateral nipple displacement, likely related to radiation-induced pectoralis muscle changes, while prepectoral irradiated reconstructions tended to have increased vertical displacement. These insights are crucial for patient education and surgical planning in the context of radiation and breast reconstruction.

Use of Tens in the Diagnosis of Functional Mandibular Lateral Deviation

Introduction: The traditional diagnosis of functional lateral deviation is based on a clinical evaluation and dental casts, supported by an instrumental analysis through X-rays; however, these diagnostic techniques do not provide any information about the neuromuscular system. Several years ago, some authors stressed the importance of the mandibular rest position and its reproducibility as a diagnostic reference, and this became possible with the development of the Myomonitor, TENS. Aim: The aim of this study was to compare mandible position before and after the use of ultra-low-frequency transcutaneous electric nervous stimulation (ULFTENS) in children with diagnosed functional mandibular lateral deviation. Methods: This study was performed on 60 children, aged between 8 and 13 years, with a mean age of 10.1 years (SD 0.81), and with functional mandibular lateral deviation diagnosed clinically, who were referred to the dental clinic for pediatric dental care. Diagnostic neuromuscular registrations were made for all children, and their casts were mounted on a Galetti articulator at the myocentric position. These casts were then compared to those provided by a wax bite registration in the intercuspidal position. Results: Compared with the existing intercuspidal position, neuromuscular registration showed improvement in 30 (50%) patients, 18 patients (30%) showed no changes, and worsening of the tooth midline discrepancy was assessed in the remaining 12 (20%). The molar relationship did not follow the same trend of the midline because of the three-dimensional changes in the maxillo–mandibular relationship induced by TENS. After TENS, there was a significant correlation between the midline and right side deviation (r &gt; 0.65); there was no correlation between the midline and the left side (r &lt; 0.65). Furthermore, the right molar movement showed no correlation with the contralateral molar (r &lt; 0.65). The posterior areas of the arch moved in a very unpredictable way, resulting in the diagnosis and prognosis of mandibular lateral deviation as absolutely individual and unpredictable. Conclusions: This study suggests that TENS-recorded occlusion is an interesting diagnostic approach in orthodontics since it allows for visualizing the trends of the neuromuscular system.

Modified surgery-first approach for management of severe class III malocclusion with maxillary skeletal midline discrepancy

This case report describes orthosurgical case that used the recently introduced surgery-first approach to correct a severe skeletal class III malocclusion with severe maxillary midline discrepancy. A 23-year-old adult male presented with severe mandibular prognathism and midline discrepancy associated with upper jaw. Firstly partial orthodontic movement were facilitated to decrowd the lower teeth in order to avoid any hindrance while anterior tooth advancement. After which prediction of the postsurgical tooth movement and surgical simulation was done by using Nemoceph software than 2-jaw surgery that included maxillary advancement differentially initiated to correct midline followed by mandibular setback was performed using a surgery-first approach. Immediate facial improvement was achieved and postsurgical orthodontic treatment was efficiently carried out. The total treatment time was 11 months. The patient's facial appearance improved significantly and a stable surgical orthodontic outcome was obtained even after patient was followed for six years.

Effects of Premature Primary Tooth Loss on Midline Deviation and Asymmetric Molar Relationship in the Context of Orthodontic Treatment.

The aim of this retrospective pilot study was to investigate the effects of premature loss of primary teeth on molar relationships and midline discrepancies in young patients and explore its potential implications for dental treatments, including orthodontics. A total of 550 study models from individuals seeking orthodontic treatment were evaluated, and 175 models met the inclusion criteria of mixed dentition. Each study model was examined for midline discrepancies, asymmetricmolar relationships, and the impact of net premature tooth loss on the midline shift. Four investigators analyzed the data, and the error was minimized to less than 5%. The study revealed that premature loss of primary first molars was significantly associated with the midline shift, while premature loss of canines and second molars did not show substantial associations with midline discrepancies. The concordance analysis between observed and expected molar classifications based on premature tooth loss indicated relatively low concordance for all three molar classes, with higher concordance observed in Class II molar relationships. Notably, premature loss of primary second molars showed higher concordance than premature loss of primary first molars. This retrospective pilot study highlights the potential dental complications associated with premature loss of primary teeth. Premature loss of primary first molars was found to be significantly linked to the midline shift, while the premature loss of canines and second molars did not demonstrate significant midline discrepancies. The concordance analysis revealed limited agreement between observed and expected molar classifications based on premature tooth loss, with higher concordance observed in Class II molar relationships and primary second molars. Further research with larger prospective cohorts and digital model analyses is warranted to gain a better understanding of the impact of premature tooth loss on dental treatment outcomes. The findings underscore the importance of early detection and appropriate intervention to mitigate potential adverse effects on dental arch development and malocclusion.

Comparable Skeletal and Dental Movements Achieved Using Conventional and Surgery-First Techniques in Class III Patients

The surgery-first (SF) approach to orthognathic surgery has been proposed as a more efficient method to correct the dentofacial deformity. This study aimed to evaluate if the magnitude of skeletal and dental changes achieved in Class III patients treated with either conventional orthognathic surgery (COS) or SF techniques differ. A retrospective cohort study of Class III orthognathic surgery patients between January 2006 and May 2020 with available pre- and post-treatment lateral cephalograms was conducted at an academic institution. The primary predictor variable was surgery technique: COS or SF. Assessed outcome variables included cephalometric skeletal parameters: SNA, SNB, ANB, Wits Appraisal, Sn-GoGn, and FMA; and dental parameters: U1-SN, U1-NA (°), U1-NA (mm), L1-NB (°), L1-NB (mm), and overjet. Within-group posttreatment parameters were analyzed with paired t tests. Pretreatment, posttreatment, and between-group parameter changes were analyzed by 2-sided 2-sample independent t tests. Potential covariates, including gender, surgical procedure, previous conventional treatment, extractions (excluding 3rd molars), crowding, and midline discrepancy, were analyzed using Fisher exact tests. Thirty-nine subjects were included in this study: 1) 21 COS (age: 20.9±8.7years) and 2) 18 SF (age: 19.6±5.0years). Cohorts were comparable (P>.05) for all analyzed covariates. COS showed statistically significant increases in L1-GoGn (3.31±6.23°; P=.024), overjet (4.26±3.99mm; P<.001), ANB (3.5±2.79°; P<.001), SNA (3.5±1.85°; P<.001), and Wits Appraisal (3.78±4.97mm; P=.002). SF showed statistically significant increases in L1-GoGn (4.19±4.85°; P=.002), L1-NB (3.08±4.13°; P=.006), L1-NB (0.79±1.35mm; P=.023), overjet (5.82±2.96mm; P<.001), ANB (5.51±3°; P<.001), SNA (4.13±2.38°; P<.001), and Wits Appraisal (5.92±3.42mm; P<.001) and statistically significant decreases in U1-NA (-3.69±7.35°; P=.048) and SNB (-1.38±2.14°; P=.014). There were no statistically significant differences in skeletal or dental parameters between groups when adjusted for pretreatment levels of that parameter. The mean treatment duration was 38months (standard deviation=12.7) in COS and 17.6months (standard deviation=5.2) in SF. The results show that skeletal and dental changes between groups were not statistically different, despite an average 20-month difference in treatment duration. This suggests that either technique can be used to achieve comparable degrees of skeletal and dental movement in Class III patients.

Comparison of the Accuracy of Maxillary Repositioning Between Using Splints and Templates in 2-Jaw Orthognathic Surgery

Printed cutting and repositioning templates could bring superior accuracy when transferring a maxillary plan to the operating room compared to a wafer-based method. However, the effect of these methods in different types of cases is inconclusive. The objective of the study was to compare the accuracy when using printed occlusal splints versus templates in simple and complicated cases. A retrospective cohort study design was used. Complicated cases were defined as cases involving impaction movement of more than 2mm, occlusal plane canting of more than 3°, or midline discrepancies of more than 2.5mm. Other cases were simple cases. Enrolled patients were randomly allocated into the digital occlusal splint (DOS) cohort and the digital templates (DT) cohort. The outcome variable was surgical accuracy, defined as the average deviation between the planned and postsurgical locations of bilateral maxillary central incisors, canines, first premolars, and first molars. Predictor variables were 1) operative complexity, simple versus complicated; and 2) technique for positioning the maxilla, DOS versus DT. Covariates were age and planned surgical movement. Two-way analysis of variance was used. Seventy patients were included in this study. Thirty-three were in the DOS cohort, and 37 in the DT cohort. The average deviation was significantly smaller in the complicated cases in the DT cohort (1.37mm; 95% confidence interval, 1.08-1.66mm) than that in the DOS cohort (2.47mm; 95% confidence interval, 1.92-3.02mm) (P=.002). The deviations in anteroposterior direction of complicated cases in the DT cohort were smaller than the corresponding values of the DOS cohort (P=.035). There is no significant difference between the deviation values of simple and complicated cases using templates (P=.116). These results indicate that in complicated cases, printed guiding templates exhibit better accuracy for repositioning the maxilla than printed occlusal splints, and the effect of templates in different cases proved to be stable.

The Effect of Symmetric and Asymmetric Loading of Frontal Segment with Two Curved Cantilevers: An In Vitro Study.

Cantilevers generate statically determined force systems. The frontal segment loading with symmetric and asymmetric cantilevers in a three-piece intrusion base arch can be used to correct midline asymmetry. Three types of 0.017″ × 0.025″ beta-titanium cantilevers: tip-back (TB), deep curve (DC), utility arch (UA) were tested on typodonts simulating intrusion of the maxillary anterior segment. Typodonts with symmetric and asymmetric cantilevers were scanned with intraoral scanner (3Shape, TRIOS, Copenhagen, Denmark) before (T0) and after (T1) the experiment, scans were superimposed using Mimics software (Materialise, Leuven, Belgium). Data were analysed with qualitative analysis. All cantilevers generated vertical and horizontal forces. For symmetric design, the DC and TB displayed intrusive force with retrusive component, UA intrusion and protrusion. The asymmetric cantilevers produced transverse displacement of anterior segment. DC created lateral, UA medial force, the anterior segment displacement was consistent with the used configuration. The movement of an anterior segment with TB is smaller compared to DC and UA. Symmetric cantilevers configurations can achieve simultaneous intrusion and retrusion or protrusion of the anterior segment. The asymmetric design with transversal force can clinically aid the correction of midline discrepancies. The effect of the cantilever configuration on delivered force direction was confirmed.

A Population-based survey on inter-arch malocclusion and background determinants

Genetics, environment, and ethnic factors are major contributors to the prevalence and variations of malocclusion.The aim of study was to determine the prevalence of interarch problems in school-aged children, 9 - 11 years, living in Tehran; and to describe the role of ethnicity, education, and economic status on them.The present data were part of the Comprehensive Evaluation of Skeleto-Dental Anomalies (CESDA) study conducted in 2015 among children living in Tehran, Iran. Cluster random sampling was applied among 19 districts of Tehran. A total of 38 schools were selected, and out of 1585 participants, the data of 1429 children were collected (response rate = 90%). The Chi-square test and binary logistic regression analysis were used for statistical analyses.Of all participants, 758 were boys and 671 were girls. The mean age was 121 ± 8 months. The most significant background determinants associated with molar relationship were ethnicity and place of residence. Class I right molar relationship was seen in 57.9% of the children and was generally more frequent in boys. Normal overjet was observed in 47.1%; 41.5% had an increased overjet, 16.2% had an anteroposterior cross-bite, and 11.8% had a lateral cross-bite. Midline discrepancy was seen among 61.1% of the children. Ideal anteroposterior, vertical, and horizontal relationship were observed in 31%, 53%, and 34% of the children, respectively. Only 10% of the children aged 9 - 11 years old had an ideal interarch relationship. Gender and place of residence had persistently significant association with having an ideal anteroposterior, vertical, horizontal, and interarch relationships (P < 0.002) in all four binary logistic regression models.The majority of the children aged 9 - 11 years old have at least one interarch problem, although it is commonly preventable.Early detection of children's orthodontic problems may help with effective prevention of further advanced anomalies.

Dental-Facial Midline: An Esthetic Based Classification

Background: The facial midline and dental midline play an important role in facial esthetics, cosmetic dentistry, facial plastic surgery, and anthropologic studies. Objective: This study studied the dental-facial midline in Nepalese subjects and to classify the midline. Methods: The study was conducted in 150 Nepalese subjects, mostly consisting of University students (80 males and 70 females). After obtaining ethical approval, facial and dental midlines were analyzed using a scale. Results: It showed 26 (18%) study subjects showed the coincidence of the facial midline with the maxillary and mandibular dental midlines. It showed that only 44 (30%) subjects showed the coincidence of facial midline with only maxillary dental midline, and 26 (17%) subjects showed the facial midline coincidence with only mandibular dental midline. The dental midline discrepancy was more prevalent in the maxillary arch and more prevalent on the right side. Midline discrepancy is seen more in males compared to females. The majority of the deviation showed 1 mm, followed by 2 mm, and 3 mm. Conclusion: The coincidence of the facial midline with both the maxillary and mandibular dental midlines is uncommon. Midline discrepancy is seen more in males compared to females. The majority of the subjects show a mild discrepancy of 1 mm. The midline discrepancy was more seen on the right side and in the maxillary arch.

A postero-anterior cephalometric evaluation of different rapid maxillary expansion appliances

The purpose of the study was to evaluate dental and skeletal changes induced by tooth-bone-borne, tooth-tissue-borne, and tooth-borne rapid maxillary expansion (RME) appliances using postero-anterior (PA) cephalometric radiographs. A total of 54 patients' (25 boys, 29 girls) PA cephalometric radiographs who had bilateral posterior crossbite and RME treatment were included and divided into three groups according to the type of appliance used during treatment: tooth-bone-borne RME appliance (hybrid Hyrax) (7 boys, 11 girls, mean age 13.28 ± 1.20 years), tooth-tissue-borne RME appliance (TTB) (8 boys, 10 girls, mean age 13.08 ± 1.06 years) and tooth-borne RME appliance (Hyrax) (10 boys, 8 girls, mean age 12.05 ± 1.35 years). Pretreatment (T0) and posttreatment (T1) PA cephalometric radiographs were analyzed with Dolphin software v. 11.7 (Chatsworth, CA). The comparisons of the groups were performed with Two-way analysis of variance. P < 0.05 was considered statistically significant. Significant and equal increase of right molar relationship and upper intermolar molar widths occurred in all groups. Dental midline discrepancy showed significant increase in only hybrid Hyrax group between T0 and T1. Significant increases were reported for lateronasal width in hybrid Hyrax and tooth-tissue-borne groups (P < 0.05). Both skeletal and dental changes were observed after RME in all groups. However, the greatest skeletal changes were seen in hybrid Hyrax and tooth-tissue-borne groups.

Dental-Facial Midline: An Esthetic Based Classification

Background: The facial midline and dental midline play an important role in facial esthetics, cosmetic dentistry, facial plastic surgery, and anthropologic studies. Objective: This study studied the dental-facial midline in Nepalese subjects and to classify the midline. Methods: The study was conducted in 150 Nepalese subjects, mostly consisting of University students (80 males and 70 females). After obtaining ethical approval, facial and dental midlines were analyzed using a scale. Results: It showed 26 (18%) study subjects showed the coincidence of the facial midline with the maxillary and mandibular dental midlines. It showed that only 44 (30%) subjects showed the coincidence of facial midline with only maxillary dental midline, and 26 (17%) subjects showed the facial midline coincidence with only mandibular dental midline. The dental midline discrepancy was more prevalent in the maxillary arch and more prevalent on the right side. Midline discrepancy is seen more in males compared to females. The majority of the deviation showed 1 mm, followed by 2 mm, and 3 mm. Conclusion: The coincidence of the facial midline with both the maxillary and mandibular dental midlines is uncommon. Midline discrepancy is seen more in males compared to females. The majority of the subjects show a mild discrepancy of 1 mm. The midline discrepancy was more seen on the right side and in the maxillary arch.

Management of Skeletal Class II in a Growing Patient Using a Headgear and a Fixed Functional Appliance, with a Three-Year Follow-up : An Indian Board of Orthodontics Case Report

This case was submitted to the Indian Board of Orthodontics under category II for phase III examination, in December 2018. SP, a 13-year-old female patient, presented with the chief complaint of forwardly placed upper front teeth. On clinical examination, she was found to have class II division 1 malocclusion with an increased overjet and overbite, a class II skeletal pattern due to a prognathic maxilla and a retrognathic mandible with positive visual treatment objective (VTO), moderate crowding in the upper and lower arches, retained deciduous 54 and 55, an exaggerated Curve of Spee, and a midline discrepancy of 6 mm. The treatment objectives were to correct the skeletal pattern and molar and canine relation. The patient was treated with fixed mechanotherapy, along with a headgear and a fixed functional appliance (Forsus). At the end of the treatment, she showed improvement in the skeletal pattern, good posterior occlusion, and an improved overjet and overbite. A bonded fixed retainer in the lower arch and a Begg’s wraparound retainer in the upper arch were used. Occlusion remained stable 3 years after the treatment.

Indications for lower incisor extraction – A case series review

Lower incisor extraction is a treatment regime since decades with its own advocates and opponents. Even though many pioneers and legends support lower incisor extraction therapy, there is still a dilemma in the orthodontic community which might be due to the fear of certain disadvantages such as formation of black triangles, midline discrepancy, loss of canine guidance, decrease in intercanine width and bite deepening. But proper case selection, treatment planning and treatment mechanics will produce stable and good results with lower incisor extraction therapy. In this article we are illustrating the specific indications of lower incisor extraction with the help of treated cases. Keywords: Mandibular incisor, Extraction, Bolton discrepancy, Adult orthodontics, Black triangle.

Occlusal Characteristics of Primary Dentition among School Going Children.

Certain characteristics of the primary dentition have been described that may be required in the smooth transition from primary to permanent dentition and therefore development of ideal occlusion in permanent dentition. The objectives of this study were to assess different occlusal characteristics of primary dentition among school going children of Dharan, Nepal and to compare these occlusal characteristics based on gender and race. A community based cross-sectional study was conducted among 625 school children of Mongolian and Caucasian race, aged 3 to 7 years, and having complete set of primary dentition. A close-ended questionnaire was developed to gather demographic information followed by the examination of occlusal and soft tissue parameters. The result showed 77.2% of the children had developmental spaces and 83.1% had primate spaces. Flush terminal plane molar and class I canine relationships were present in 68.8% and 81.6%, respectively with normal overjet (53.5%), normal overbite (41.1%), straight facial profile (86.7%) and competent lips (98.6%). Crowding was present in 35.4%, midline discrepancy in 11.3%, crossbite in 7.2%, scissor bite in 0.6% and open bite in 2.1% of the children examined. Most of the occlusal characteristics were desirable but with the existence of some malocclusion traits, necessitating timely recognition and correction through early screening. Gender and racial influences were also observed and it emphasizes the need for treatment plan based on them.

Digital Occlusion Setup Is Quantitatively Comparable With the Conventional Dental Model Approach: Characteristics and Guidelines for Orthognathic Surgery in Patients With Unilateral Cleft Lip and Palate.

The evolving 3-dimensional computer-based technology revolutionized the field of orthognathic surgery (OGS). Digital occlusion setup for OGS may provide advantages in the planning comparing with the conventional approach based on the manual setup using dental casts, but we are not aware of any study focusing on digital occlusion setup for cleft OGS. The purposes of this study were to compare the conventional and digital occlusion setup approaches and to propose a protocol for digital occlusion setup in unilateral cleft OGS. Thirty consecutive patients with unilateral cleft lip/palate who underwent orthodontic treatment by a single orthodontist and 2-jaw OGS by a single surgeon using 3-dimensional surgical simulation were adopted for analysis. Quantitative data were collected from the dental cast occlusion setup approach (conventional group). A multidisciplinary team combined this quantitative data and established a protocol for digital occlusion setup in cleft OGS. Digital occlusions were set according to this protocol using the images of the 30 patients, and quantitative data were collected accordingly (digital group). The results of 2 groups were compared. All information was reviewed to refine the protocol and define the final guidelines. There were no significant differences (all P > 0.05) for all parameters, except midline discrepancy (conventional group > digital group, P < 0.001). The root-mean-square deviation (0.46 ± 0.26 mm) indicated acceptable relationship between the conventional and digital groups. A 6-step protocol for digital occlusion setup in cleft OGS was established: dental midline, overjet/overbite, yaw rotation, pitch rotation, roll rotation, and overall facial skeletal appearance. This study shows that digital occlusion setup is quantitatively comparable with the conventional dental model approach and contributes for cleft OGS by establishing a protocol for surgical occlusion setup using digital approach.

New protocol for in-house management of computer assisted orthognathic surgery

The aim of this study was to evaluate retrospectively the accuracy of a protocol for completely in-house, computer-assisted, orthognathic surgery, generating resin printed intermediate surgical guides. A retrospective, observational study was made on a cohort of 15 patients treated consecutively from September 2017 to May 2019, who underwent bimaxillary orthognathic surgery planned with the same 3-dimensional program and whose surgical intermediate splints were obtained with the same all-in-house protocol. Virtual planned surgical movements were compared with the real surgical outcome. The differences were not significant for eight of the 12 variables considered. The p values, calculated with the Wilcoxon signed rank test, were evenly distributed and ranged from p=0.001 to p=0.820. Significant differences were reported in four measurements: angle between sella-nasion plane and a line connecting the incisal edge and the apex of the root of the most prominent incisor (U1-SN) (p=0.001), angle between Frankfort plane and a line connecting the incisal edge and the root apex of the most prominent upper incisor (p=0.008), dental midline discrepancies (p=0.006), and occlusal plane tilt (U1-FH) (p=0.001), basically due to intraoperative settings. The 3-dimensional resin printed surgical guides were shown to be a reliable alternative to the commercial ones and showed high rate of accuracy for most of the variables assessed. Four out of 12 of these showed significant errors, but two of them were only minimal discrepancies with no clinical implications.

Evaluation of Facial and Dental Midline Discrepancies in Nepalese Population

Introduction: The facial midline is defined by the landmark such as the nose, philtrum, and chin aligned in a straight line. It should be in the center of the face and should coincide with the dental midline. But clinically it is often observed that some discrepancies exist between facial and dental midlines. Thus the aim of this study was to evaluate the facial and dental midline discrepancies.&#x0D; Methods: A total of 300 subjects, 150 male and 150 female from People’s Dental College and Hospital were selected. Full facial view standardized photograph with a posed smile with teeth in occlusion was taken with Canon 400D digital SLR. For standardized measurement vertical metallic scale with millimeter, markings were placed on the right side of the patient in all cases. The software program Digimizer image analysis (version 4.6.1) was used to determine the facial and maxillary dental midline.&#x0D; Result: This study showed 6.66% of male and 12% of female had perfectly coinciding F1 facial midline (perpendicular from the midpoint of inner canthus distance), F2 facial midline (line joining the midpoint of inner canthus and the midpoint of the base of the nose) and maxillary midline. 26% of males and 28% of females had less than 1mm of the discrepancy of F1 midline to maxillary midline whereas 41% of males and 38% of females had less than 1 mm of a discrepancy between F2 facial midline and maxillary midline. The study also showed that 24% of males and 24.66% of females had none coincidence of any of the midlines with one another.&#x0D; Conclusion: Most of the Nepalese have noncoinciding facial and dental midline but females have more coinciding midlines in comparison to males. The shifted facial midlines are more towards the left side in relation to maxillary dental midline.

Balancing the dental occlusion and facial aesthetic features in cleft orthognathic surgery: Patient-centered concept for computer-aided planning

Patients with cleft lip and palate could develop dentofacial deformity characterized by malocclusion, midface retrusion, midline discrepancy and asymmetry. Cleft orthognathic surgery has evolved from the simple maxillary LeFort I advancement with correction of dental malocclusion to the current model of patient-centered approach focusing on skeletofacial reconstruction using computer-assisted diagnosis and planning. Three-dimensional imaging and surgical simulation have provided valuable information for facial aesthetics and surgical feasibility. Surgery-first approach and two-jaw orthognathic surgery have gradually become prevalent replacing the conventional method. A better dentofacial outcome is achieved with reduction of the burden of care.