Occlusal Plane Angle Research Articles

Functional Units Analysis of Mandibular Morphology in Patients With Parry-Romberg Syndrome.

To characterize mandibular morphology in patients with Parry-Romberg syndrome (PRS). Retrospective study. A craniofacial center. Thirty-three patients with PRS affecting mandible. Preoperative computed tomography data were analyzed using Mimics 26.0 (Materialise Inc.). Distances between landmarks-condyle process (Con), coronoid process (Cor), mandibular foramen (IAF), gonion (Go), and mental foramen-were measured to represent the sizes of skeletal units. Positional asymmetry was reflected by angles between lines connecting bilateral landmarks and the occlusal plane. Bilateral differences in unit sizes were compared. Absolute difference (Δ) > 5 mm and relative size (RS) < 80% were set to evaluate the severity of hypoplasia. Angular measurements were compared to 0° using one-sample t tests. Pearson correlation analysis was conducted to examine the relationship between onset ages and both RS and angular measurements. The affected side's skeletal units were smaller. Severe hypoplasia was more common in the angular unit. Angles between Con-Con', Cor-Cor', IAF-IAF', and the occlusal plane were less than 0°, whereas the angle with Go-Go' was greater than 0°. Age of onset was positively correlated with the condylar unit size and the Con-Con' to occlusal plane angle. Patients with PRS affecting mandible exhibit smaller skeletal units on the affected side, particularly in the angular unit. Most landmarks on affected side tend to cluster toward the occlusal plane. Earlier onset of PRS correlates with more pronounced condylar asymmetry. Evaluating the severity of functional units involvement and implementing appropriate treatment should be considered.

Evaluation of Treatment Effects of en Masse Mandibular Arch Distalization Using Skeletal Temporary Anchorage Devices: A Systematic Review.

Mandibular arch distalization using temporary anchorage devices (TADs) is effective in correcting borderline Class lll cases without surgery. This review analysed the existing literature evaluating the dental, skeletal, and soft tissue changes after en masse mandibular arch distalization using TADs. We followed PRISMA guidelines and registered this review in PROSPERO database CRD42023450524. PubMed, Google Scholar, Cochrane, Web of Science, and SCOPUS databases were searched. Orthodontic patients requiring en masse mandibular distalization using TADs were compared with different modalities of distalization. Dental changes were evaluated along with skeletal and soft tissue changes and treatment duration. Randomized controlled trials (RCTs), cohort studies, longitudinal studies, and retrospective studies were eligible to be included. The risk of bias was assessed using ROBINS-I tool ("Risk Of Bias In Non-randomized Studies-of Interventions"). Of 1764 identified records, seven studies (one non-RCT, one prospective clinical trial, and five retrospective cohort studies) were included. One study had a low risk of bias, three had moderate bias, two had serious bias, and one had critical bias. All studies showed molar distalization and distal tipping with significant retraction of the lower lip. Miniplates showed greater distalization compared to miniscrews. Interradicular miniscrews exhibited the least distal tipping. Changes in SNB, ANB, occlusal plane angle, and mandibular plane angle were reported. Retromolar screws and ramal plates reported reduced treatment duration. TADs are effective in en masse distalization of mandibular dentition with intrusive or extrusive effects.

Characteristics of the Occlusal Plane Associated with Unilateral and Bilateral Articular Eminence Inclination: A Cross-Sectional CBCT Study.

The characteristics of the temporomandibular joint (TMJ) are essential in orthodontic and prosthetic treatments. Previous studies have suggested an association between articular eminence inclinations (AEI) and occlusal plane characteristics using radiographs, but no bilateral analysis has been conducted using cone beam computed tomography (CBCT). Objective: This study aimed to investigate the specific characteristics of the occlusal plane inclinations associated with unilateral and bilateral AEI using CBCT. Methods: We conducted a cross-sectional study to evaluate 200 temporomandibular joints (TMJs) from 100 records obtained at the orthodontic department. We evaluated the association between the AEI, and occlusal plane characteristics like the cant of the occlusal angle, occlusal plane angles, inclination of the upper incisor to the Frankfort plane and palatal plane using both bivariate and multivariate analyses both unilaterally and bilaterally. Results: Our findings suggested statistically significant associations (p < 0.050) between AEI (bilateral) and occlusal inclination parameters, including the cant of the occlusal plane (Coef. -0.38; 95%CI -0.70:-0.06; p = 0.017), occlusal plane angle (Coef. -0.39; 95%CI -0.740:-0.05; p = 0.024), and position of the upper incisor relative to the palatal plane (Coef. -0.34; 95%CI -0.63:-0.06; p = 0.016). Conclusion: This study suggests an association between dental inclinations and AEI, which reflects the anatomical characteristics of TMJ and its related dental structures.

A novel approach for posterior bite collapse in an adult with crossbite anterior using a 3D-printed bite riser

Background: Managing an adult patient presenting with an anterior crossbite in conjunction with posterior bite collapse (PBC) is a difficult challenge. Purpose: The purpose of this case study is to highlight the accuracy that can be attained with the utilization of a three-dimensional (3D) printed bite riser in the correction of PBC accompanied by an anterior crossbite in an adult patient with Class III malocclusion. Case: A 64-year-old male complained of being unable to chew properly. Extraoral examination revealed a concave profile with a protrusive mandible. The patient exhibits a 5 mm anterior crossbite and has missing lower posterior molars, resulting in bilateral PBC. The cephalometric analysis revealed skeletal Class III patterns (SNA: 82.19o; SNB: 86.34o; ANB: -4.15°), with protrusion and counterclockwise rotation of the mandible (SN-OP: 3.84o). Case Management: By utilizing a 3D-printed bite riser in conjunction with temporary anchoring devices (TADs), it is possible to resolve the issue of an anterior crossbite accompanied by PBC. This is achieved by repositioning the elongated posterior segments on both sides of the maxilla to generate vertical space for mandibular tooth rehabilitation, retracting the anterior segment, and narrowing the lower arch. Simultaneously, the crossbite on both sides was corrected, a Class I and ideal overbite and overjet were achieved, the occlusal vertical dimension increased, the occlusal plane angle was corrected (7.51o), and an acceptable ANB angle (-1.36°) was accomplished. The treatment lasted 18 months and yielded sustained results after a one-year retention period. Conclusion: Integrating 3D printing technology in orthodontic treatment offers numerous options for managing challenging cases such as PBC while also reducing the treatment length. The patient was satisfied with the results achieved.

Changes in 3-Dimensional Measurements of Masseter Muscle After Orthognathic Surgery in Patients with Facial Asymmetry

ObjectiveThe aim of this study was to quantitatively evaluate morphological and volumetric changes in the masseter muscle using 3-dimensional analysis of facial asymmetry patients and to identify factors influencing these changes before and after orthognathic surgery.Methods[Reviewer1 (2)]A single-center retrospective cohort study was conducted on twenty-two patients with deviation of the chin > 4 mm. Masseter muscle volume and morphology were measured at different periods during long-term follow-up (mean 15 ± 3.2 months). Factors related to changes in masseter muscle cross-sectional area and volume analyzed were also analyzed.Results[Reviewer1 (2) and (9)]The volume and cross-sectional area of the masseter muscle on the non-deviated side reduced by 13.5% (P < 0.05) and 16.4% (P < 0.05), respectively, after orthognathic surgery. The length of the masseter muscle increased by 13.9% on the deviated side (P < .05) but decreased by 11.7% on the non-deviated side (P < 0.05). The width decreased on the deviated side from T1 to T2 (13.51 ± 2.09 mm vs. 12.04 ± 1.39 mm), but the non-deviated side showed an opposite tendency (10.81 ± 1.31 mm vs. 12.69 ± 2.37 mm). The difference in masseter muscle length and width between the two sides significantly reduced after surgery (P < 0.05). There was a noticeable decrease in the asymmetry in the muscle in proportion to the degree of the occlusal plane angle.ConclusionMasseter muscle asymmetry exists in patients with facial asymmetry, but it could be improved with maxilla-mandible correction. Atrophy of the masseter muscle after orthognathic surgery was greater in patients with a large inclined occlusal plane angle due to improved dental compensation.Level of Evidence IVThis journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

The correlation analysis between incisal guidance angle and occlusal plane angles and temporomandibular joint morphology.

The correlations between the incisal guidance angle (IGA) and occlusal plane angles and temporomandibular joint (TMJ) morphology were investigated in adults with skeletal Class II division II malocclusion. CBCT images of 37 patients were analyzed. It included 19 cases of skeletal Class II division II malocclusion with low angle (study group) and 18 cases of skeletal Class I average angle (control group). The Invivo Dental 5 software was employed to acquire the data of the incisal guidance angle (IGA), occlusal plane angle (FH-OP), anterior occlusal plane angle (FH-AOP) and the TMJ measurement items. The results of IGA, FH-AOP angle and FH-OP angle showed the study group > the control group (P < 0.05). There were statistically difference in the condylar mediolateral diameters, articular eminence inclination and height, and posterior joint spaces between two groups. No differences were revealed in the condylar anteroposterior diameters, the condylar inclination angle, condylar head width and height, condylar length, glenoid fossa depth and width between two groups. In the study group, IGA showed a moderate correlation with FH-AOP, a weak correlation with FH-OP and condylar mediolateral diameters. Meanwhile, there was a correlation between FH-AOP, FH-OP, and TMJ indicators. The IGA was not only related to FH-AOP and FH-OP, but also to the condylar mediolateral diameters. In addition, there was a correlation between the occlusal plane angles and TMJ morphology in skeletal Class II division II low angle malocclusion. For patients with skeletal Class II division II low angle malocclusion, adjusting the IGA and the occlusal plane angles could improve the esthetic appearance of the anterior teeth, occlusal function, and TMJ morphology.

Effects of different intrusion patterns during anterior teeth retraction using clear aligners in extraction cases: an iterative finite element analysis.

Overtreatment design of clear aligner treatment (CAT) in extraction cases is currently primarily based on the clinical experience of orthodontists and is not supported by robust evidence on the underlying biomechanics. This study aimed to investigate the biomechanical effects of overtreatment strategies involving different maxillary anterior teeth intrusion patterns during anterior teeth retraction by CAT in extraction cases. A finite element model of the maxillary dentition with the first premolar extracted was constructed. A loading method of clear aligners (CAs) based on the initial state field was proposed. The iterative method was used to simulate the long-term orthodontic tooth movement under the mechanical load exerted by the CAs. Three groups of CAs were utilized for anterior teeth retraction (G0: control group; G1: incisors intrusion group; G2: anterior teeth intrusion group). Tooth displacement and occlusal plane rotation tendency were analyzed. In G0, CAT caused lingual tipping and extrusion of the incisors, distal tipping and extrusion of the canines, mesial tipping, and intrusion of the posterior teeth. In G1, the incisors showed minimal extrusion, whereas the canines showed increased extrusion and distal tipping tendency. G2 showed the smallest degree of posterior occlusal plane angle rotation, while the inclination tendency of the canines and second premolars decreased. 1. In CAT, tooth displacement tendency may change with increased wear time. 2. During anterior teeth retraction, the incisor intrusion pattern can provide effective vertical control for the lateral incisors but has little effect on the central incisors. Anterior teeth intrusion patterns can alleviate the inclination of canines and second premolars, resulting in partial relief of the roller-coaster effect.

Evaluation of Cephalometric Downs Analysis on Cephalograms at RSGM YARSI, Jakarta

Introduction: Cephalometric analysis is used to help establish diagnosis and treatment plan in orthodontics. One of the cephalometric analysis is the Downs analysis which its standard values were measured in Caucasians. However, these values cannot be applied to other races and ethnicities because there are racial and ethnic variations. Hence, it is necessary to know the average value for Indonesians. Objective: This study aimed to evaluate Downs analysis on cephalograms at RSGM YARSI Jakarta, compare it with Downs’ norms and other ethnicities, and determine differences between gender. Materials and Methods: Measurements of 10 parameters of Downs analysis were carried out on 29 cephalograms. Data were tested statistically. Results: The mean of the facial angle are 85.17°±3.07; angle of convexity 3.62°±2.79; AB plane angle AB -2.65°±2.55; mandibular plane angle 29.82°±3,37; Y-axis 64.15°±3.34, occlusal plane angle 11°±2.86; interincisal angle 113.06°±7.64; LI-occlusal angle 28.41°±5.24; IMPA angle 10.24°±5.76; distance of UI-APog 8.05 mm±1.85. Discussion: The RSGM YARSI cephalometric value compared to the Downs’ norms shows that the chin towards the FHP is more retroposition, the face is more convex, the relationship of the lower and upper jaw to the NPog is more protrusive, the direction mandibular growth towards the FHP is more vertical, the direction of facial growth is more downward, occlusal growth towards the FHP is steeper, and the incisors are more protruded. The direction of growth in male is more vertical than in female, and there are differences in cephalometric values with other races. Conclusion: There is a significant difference between the Downs cephalometric values of RSGM YARSI and the Downs’ norms in all measurements. Between men and women at RSGM YARSI there are gender differences in the direction of growth. There are differences in measurement values with other races.

Effects of clear aligners on the vertical position of the molar teeth and the vertical and sagittal relationships of the face: a preliminary retrospective before-after clinical trial

IntroductionDespite the popularity of clear aligners, their predictability has not been assessed adequately. Moreover, no study has investigated their effects on numerous dentomaxillary variables. Therefore, this study was conducted for the first time, assessing several new or controversial items. The aim of the study was to evaluate the effects of clear aligners on the vertical position of the molar teeth and the vertical and sagittal relationships of the face.MethodsThis preliminary retrospective before-after non-randomized clinical trial was performed on 168 observations of 84 patients (33.60±9.28 years, 54 females) treated with 0.75mm Invisalign appliances. Pretreatment and posttreatment values were measured for: mandibular plane angle, occlusal plane angle, Y-Axis, ANB, facial angle, lower anterior facial height, overbite, and the distances of the molars from the palate and mandibular plane were measured. The alterations in parameters caused by treatment (delta values) were calculated for each measurement. Effects of treatment and some parameters on delta values were analyzed statistically (α=0.05).ResultsMean±SD of ΔMP-FH, ΔOP-FH, ΔY-Axis, ΔLAFH, ΔNPog-FH, ΔANB, ΔOverbite, ΔSNB, Δ6-PP, Δ7-PP, Δ6-MP, and Δ7-MP were respectively 0.11±1.61, 0.80±1.56, 0.15±1.18, 0.07±0.91, -0.22±1.25, 0.03±0.62, 0.04±1.15, -0.06±1.14, -0.36±0.94, -0.32±1.14, 0.19±0.96, 0.18±1.10. Only the alterations in OP-FH, 6-PP, and 7-PP were significant (P≤0.011). Age, sex, treatment duration, or pretreatment mandibular plane angle were not correlated with any delta values. However, the pretreatment occlusal plane angle was negatively correlated with ΔOP-FH and ΔY-Axis. Crowding was correlated negatively with ΔOP-FH and ΔY-Axis and positively with ΔNPog-FH. Overjet was negatively correlated with ΔANB and ΔOverbite (P≤0.035).ConclusionsInvisalign intruded first/second maxillary molars and increased the occlusal plane angle. Age, sex, and treatment duration were not correlated with post-treatment anatomic alterations.

Comparison of Class II open bite correction by temporomandibular joint prostheses or bimaxillary orthognathic surgery

IntroductionThe aim of this study was to evaluate the outcome of skeletal Class II and anterior open bite patients who received simultaneous Le fort I osteotomies with temporomandibular joint (TMJ) prostheses or bimaxillary orthognathic surgery. Materials and MethodsPatients with condylar resorption (CR) were treated by TMJ prostheses and orthognathic surgery and divided into two groups. Cephalometric radiographs were obtained before and after operation to find out the surgical alteration by comparing measures at different time points. Results23 patients were included. Mean overbite of the patients was increased by 3.39 mm in TMJ prostheses group and 3.24 mm in orthognathic group. Occlusal plane angle was averagely rotated -6.06° and 1.31°; mandibular plane counterclockwise rotated 12.23° and 5.81°, respectively. The increase of ramus height in TMJ prostheses group were significantly greater than orthognathic surgery group (8.02 ± 1.96 mm vs. -0.09 ± 1.29 mm). The overall treatment effect was stable in both groups during the 1-year follow up. DiscussionTwo surgical plans seem to be reliable treatments of anterior open bite and mandibular retrognathism caused by temporomandibular disease. TMJ prostheses with simultaneous Le fort I osteotomies close open bite by lengthening the height of ramus and rotating maxillo-mandibular complex counterclockwise, while bimaxillary orthognathic surgery by rotating maxilla clockwise and mandible counterclockwise without rebuilding ramus.

Reinventing serial extraction with a fresh perspective: does it inspire a change in current practice?

To analyze the skeletal and dental effects of serial extraction with and without expansion on severe crowding. A retrospective controlled study using lateral cephalograms of 78 children of age 8.5 + /- 1.4 years. The study sample involved 52 orthodontic patients treated for severe crowding and 26 age matched controls who did not undergo orthodontic treatment. The treated cases were sorted into serial extraction (EX) only group and serial extraction and expansion (EX-EXP) group. Vertical and anteroposterior skeletal and dental cephalometric measurements of these subjects were analyzed at baseline time point and following eruption of posterior permanent dentition. The study found significant changes in vertical skeletal dimensions with a decrease in mandibular and occlusal plane angles in the experimental groups at the follow up. The facial height index was noted to be increased. The upper gonial angle decreased significantly in the groups that had extractions. There was no significant change in the inter-incisal angle among the groups, yet at follow-up the inter-incisal angle of the control group was significantly smaller than the intervention groups. The article concludes that serial extraction alone or in combination with expansion treatment performed prior to pubertal growth phase have comparable skeletal cephalometric findings primarily affecting the vertical dimension.

Association of Anterior and Posterior occlusal planes with skeletal class I, class II and class III malocclusion

Introduction: The occlusal plane is a very vital in stomatognathic system and the association between anterior occlusal planes and posterior occlusal plane plays an important role during orthodontic treatments. Methods: Lateral cephalometric radiographs of 270 adult patients of the different classes of malocclusion were used. Several angular measurements were measured and compared among all study groups to evaluate the existence of relationship between AOP and POP with skeletal and vertical patterns. Results: The skeletal patterns showed a significant difference in anterior occlusal plane angle relative to both SN plane and FH plane among all classes of malocclusion (p-value =0.001**) having a steeper inclined plane in Class II and flat inclined plane in Class III. POP in relation to FH plane and SN plane showed lowest angle in skeletal Class III and highest in Skeletal Class I patients. Conclusion: The occlusal planes were found to have an impact on the jaw base where the variation in its angulation of different occlusal planes had affected both sagittal and vertical facial patterns. AOP relative to SN and FH were steeper in Class II and flat in Class III, while the POP relative to FH showed the same value in Classes II and III. Keywords: Anterior occlusal plane, Posterior occlusal plane, Malocclusion, Skeletal patterns, Vertical pattern, Lateral cephalometric radiograph.

Occlusal Plane Angle as a Key Factor for Chin Protrusion After Mandibular Osteotomy in Skeletal Class III.

There is no treatment algorithm to decide whether maxillomandibular or mandibular osteotomy alone should be performed in borderline cases. This study assessed the factors that affect the changes in soft tissue after mandibular setback. Patients who underwent mandibular osteotomy alone to correct mandibular protrusion were included in this study. Hard and soft tissue analyses were performed on lateral cephalograms before and 12±3 months after surgery. The popular points were set for referencing hard and soft tissues on the lateral cephalogram. Nasolabial, labiomental, and soft tissue facial plane angles were measured for the soft tissue assessment. To assess the mandibular setback amount, SNB was calculated. Twenty-one patients were included in this study. The nasolabial angle was increased after surgery and its change significantly correlated with the change in SNB ( P =0.00815). The change in soft tissue facial plane angle after surgery per change in SNB significantly correlated with the occlusal plane angle ( P =0.0009). An occlusal plane angle of at least 15.45 degrees was required for the SNB and soft tissue facial plane angle to change to the same degree. The occlusal plane angle (whether or not it was ≥15.45 degrees) may help in determining the surgical approach in borderline cases, specifically on whether maxillomandibular or mandibular osteotomy alone should be performed if the mandibular setback is simple.

Evaluation of accuracy of maxillary repositioning surgery using an observer-independent method

ObjectiveTo evaluate the accuracy of maxillary repositioning in two-jaw surgery using computer-aided surgical simulation (CASS) and computer-aided design/manufacturing (CAD/CAM) splints by using a highly accurate observer-independent method. MethodsA retrospective evaluation was conducted of 30 consecutive adults who underwent Le Fort I osteotomy by a single surgeon. Surgical planning and fabrication of occlusal splints were performed using custom-developed CASS software. Preoperative images with landmarks were superimposed on postoperative images to evaluate discrepancies between the planned and actual position of the maxilla following surgery. Translational and rotational differences were expressed as the root mean square deviation (RMSD). The number of cases that exceeded the clinically acceptable limits (2 mm for the translational difference at the centroid, 4° for the rotational difference, and 1 mm for the mediolateral difference at the dental midline) were also evaluated. ResultsPostoperative anteroposterior translation and pitch values were significantly different to and negatively correlated with the planned values, respectively. The largest translational RMSDs at the centroid and the dental midline were 1.04 mm and 1.03 mm, respectively, in the anteroposterior direction. The largest rotational RMSD was 1.86° in pitch. The percentage of discrepancies exceeding the clinically acceptable limit was 3.3% for the centroid, 3.3% for rotation, 20.0% for the midline, and 26.7% for any one criterion. ConclusionWhile maxillary repositioning using CASS and CAD/CAM splints was accurate on a population level, there remains potential for clinically significant errors to occur on an individual level, particularly in controlling the dental midline position and occlusal plane angle.

A Novel Imaging Technique for Analyzing Condylar Movement During Mastication in Patients With Jaw Deformities: Four-Dimensional Computed Tomography.

This study aimed to reveal characteristic condylar movements in patients with jaw deformities. Thirty patients with jaw deformities before surgery were enrolled and instructed to chew a cookie during 4-dimensional computed tomography (4DCT). The distance between the most anterior and posterior positions of the bilateral condyles on 4DCT images was measured and compared among patients with different skeletal classes. Correlations between the condylar protrusion and cephalometric values were also determined. The distances of condylar protrusion during mastication were significantly greater in the skeletal class II group than in the skeletal class III group ( P =0.0002). Significant correlations were found between the distances of condylar protrusion during mastication and the sella-nasion-B point angle ( r =-0.442, P =0.015), A point-nasion-B point angle ( r =0.516, P =0.004), sella-nasion plane to ramus plane angle ( r =0.464, P =0.01), sella-nasion plane to occlusal plane angle ( r =0.367, P =0.047), and condylion-gonion length ( r =-0.366, P =0.048). Motion analysis with 4DCT images revealed that condylar movement in patients with retrognathism was larger than in patients with mandibular prognathism. Skeletal structure was therefore correlated with condylar movement during mastication.

Orthognathic surgery effects on temporomandibular joint compressive stresses.

This study tested orthognathic surgery effects on temporomandibular joint (TMJ) compressive stresses. Pre- (T1) and post-surgery (T2) cone-beam computed tomography images were collected from consenting subjects aged ≥15 years. Anatomical data were used to measure surgical changes in anteroposterior mandibular position and occlusal plane angle (FH-OP), estimate condylar loading areas (mm2 ) and calculate T1 and T2 TMJ and jaw muscle forces (N) during canine biting via numerical modelling. Analysis of covariance tested for sex and biting angle differences in T2 - T1 TMJ compressive stresses (TMJ force/loading area, MPa). Principal component analyses identified jaw muscle forces that accounted for changes in T2 - T1 TMJ loads. Regression analyses tested the correlations between surgical changes in mandibular position, FH-OP, TMJ loads and muscle forces. Of 148 cases screened, 28 females and 16 males provided complete records. Condylar loading areas were significantly smaller (P = .024) for females vs males (124 ± 5 vs 144 ± 7 mm2 ). T2 - T1 differences in TMJ compressive stresses varied by surgical change, biting angle and sex. Overall, the largest increases in TMJ compressive stresses post-surgery were for females with mandibular setbacks where FH-OP angle decreased. T2 - T1 changes in jaw muscle forces had moderate (ipsilateral, λ = 4.59; η2 = 0.071) to large (contralateral, λ = 1.49; η2 = 0.31) effects on TMJ loads. T2 - T1 differences in TMJ compressive stresses during canine biting were affected by surgical changes in mandibular position and occlusal plane angle, biting angle and sex. Surgical changes altered jaw muscle forces for the same biting conditions and, thus, affected TMJ loads and compressive stresses.

Comparison of Steiner Cephalometric analysis of lateral skull X-ray images with CBCT in a group of students of the dental school of the University of Cuenca

The Steiner analysis from images obtained from cone beam computed tomography is one of the essential tools today for diagnosis in the area of orthodontics, within this aspect its high value for the study of points, angles and cephalometric planes allows the prediction of the possible treatment plan for each patient according to the specific characteristics resulting in each patient. Objective: To compare the results in Steiner cephalometric measurements obtained in 2D lateral skull radiographs and in 3D cephalograms generated from Cone Beam Computed Tomography (CBCT). Methodology: Type of comparative analytical study. A non-probabilistic sample was established by convenience consisting of 29 diagnostic studies divided into: 29 lateral skull X-rays and 29 standardized CBCT. Subsequent localization, tracing and measurement of skeletal and dental angles were performed according to Steiner's cephalometric analysis using Nemostudio 2022 software. The study and analysis was performed using the Intraclass Correlation Coefficient. Results: The mean difference between the skeletal angles SNA, SNB, ANB, SND and Occlusal Plane Angle showed that there is no significant discrepancy when performing a cephalometric analysis in three-dimensional images compared to two-dimensional images. Conclusion: There is a high degree of reliability and accuracy of cephalometric measurements for obtaining skeletal and dental angles in two-dimensional images obtained from a CBCT with respect to a lateral radiograph.

Craniofacial Morphology of Temporomandibular Disorder Patients with Different Disc Positions: Stratifying Features Based on Sex and Sagittal Skeletal Pattern.

Disc displacement (DD) appears in the majority of temporomandibular disorder (TMD) patients. The correlation between craniofacial morphology and different disc positions has been underlined, while the craniofacial morphological differences based on sex and sagittal skeletal pattern stratification have been insufficiently studied. In this study, 304 patients with TMD complaints were included and classified into normal position, disc displacement with reduction (DDwR) and disc displacement without reduction (DDwoR) groups according to magnetic resonance imaging. A total of 24 cephalometric measurements, covering the cranial base, vertical relationship, sagittal relationship, mandible position and morphology, and dental relationship, were assessed using lateral cephalograms. A stratified analysis was performed based on the sex and sagittal skeletal pattern. Overall, DD patients had distinctive craniofacial morphological features. The posterior cranial base length and mandibular arc angle were statistically different only in females, while the Y-axis angle, occlusal plane angle and sella nasion point A angle (SNA) might be unique features in males. Skeletal class II had the most statistically different measurements compared to the others. Differences in the Frankfort mandibular incisor angle (FMIA) and saddle angle were especially displayed in skeletal class III patients. The sex and skeletal sagittal pattern could affect the morphological differences in TMD patients with different disc positions.

Comparison between clear aligners and twin-block in treating class II malocclusion in children: a retrospective study.

The study herein evaluated and compared the efficacy of Clear Aligners (CA) and Twin-Block (TB) appliances as the early orthodontic treatments of developing class II division 1 malocclusion. Twenty-four patients each for CA (11.73 ± 0.33 y) and TB (11.87 ± 0.34 y) groups were selected according to the inclusion and exclusion criteria. The cephalometric X-rays and intraoral photos were taken for the patients after nearly 12 months of treatment. Treatment impacts were evaluated by the molar correction and overjet reduction. The vertical and sagittal changes were analyzed through cephalometric measurements. Sella-nasion-point B angle (SNB), point A-nasion-point B angle (ANB), Wits Appraisal (AO-BO) and overjet were statistically significant regarding the sagittal changes analyzed before and after the treatments in both groups, respectively. So, no significant difference was noted in the sagittal changes between CA and TB groups. However, for the vertical changes, OP (occlusal plane) angle of CA group and OP angle, AFH (anterior facial height) and PFH (posterior facial height) of TB group were statistically significant. Moreover, the Z angle and cranial facial difficulty (C.F. difficulty) were also statistically significant in both groups. Class II children with retrognathic mandible are effectively treated by employing the CA, which has almost the same impact as of TB in sagittal and vertical changes. Resultantly, the patient profile is improved. The CA and TB treatments thus minimize the subsequent treatment difficulty by reducing the C.F. difficulty.

Intra- and Interrater Agreement of Face Esthetic Analysis in 3D Face Images.

The use of three-dimensional (3D) facial scans for facial analysis is increasing in maxillofacial treatment. The aim of this study was to investigate the consistency of two-dimensional (2D) and 3D facial analyses performed by multiple raters. Six men and four women (25-36-year-old) participated in this study. The 2D images of the smiling and resting faces in the frontal and sagittal planes were obtained. The 3D facial and intraoral scans were merged to generate virtual 3D faces. Ten clinicians performed facial analyses by investigating 14 indices of 2D and 3D faces. Intra- and interrater agreements of the results of 2D and 3D facial analyses within and among the participants were evaluated. The intrarater agreement between the 2D and 3D facial analyses varied according to the indices. The highest and lowest agreements were found for the dental crowding index (0.94) and smile line curvature index (0.56) in the frontal plane, and Angle's classification (canine) index (0.98) and occlusal plane angle index (0.55) in the profile plane. In the frontal plane, the interrater agreements were generally higher for the 3D images than for the 2D images, while in the profile plane, the interrater agreements were high in the Angle's classification (canine) index however low in the other indices. Several occlusion-related indices were missing in the 2D images because the posterior teeth were not observed. Esthetic analysis results between 2D and 3D face images can differ according to the evaluation indices. The use of 3D faces is recommended over 2D images to increase the reliability of facial analyses, as it can fully assess both esthetic and occlusion-related indices.