Effects of adenoid hypertrophy on nasopharyngeal airway ventilation: A computational fluid dynamics study

OBJECTIVES

Adenoid hypertrophy causes impaired nasopharyngeal airways (NA) ventilation. However, it is difficult to evaluate the ventilatory conditions of NA. Therefore, this study aimed to analyze the nasopharyngeal airway resistance (NARES) based on computational fluid dynamics simulations and the nasopharyngeal airway depth (NAD) and adenoid hypertrophy grade measured on cephalometric cone-beam computed tomography images and determine the relationship between NAD and grade and NARES to ultimately assess using cephalometric measurements whether NA has airway obstruction defects.

METHODS

Cephalogram images were generated from cone-beam computed tomography data of 102 children (41 boys; mean age: 9.14 ± 1.43 years) who received orthodontic examinations at an orthodontic clinic from September 2012 to March 2023, and NAD and adenoid grade and NARES values were measured based on computational fluid dynamics analyses using a 3D NA model. Nonlinear regression analyses were used to evaluate the relationship between NARES and NAD and correlation coefficients to evaluate the relationship between grade and NARES.

RESULTS

NARES was inversely proportional to the cube of NAD (R2 = 0.786, P < 0.001), indicating a significant relationship between these variables. The resistance NARES increased substantially when the distance NAD was less than 5 mm. However, adenoid Grade 4 (75 % hypertrophy) was widely distributed.

CONCLUSIONS

These study findings demonstrate that the ventilatory conditions of NA can be determined based on a simple evaluation of cephalogram images. An NAD of less than 5 mm on cephalometric images results in NA obstruction with substantially increased airflow resistance.

SIDS plane: A simple and innovative alternative to Frankfurt horizontal plane

AIMS AND OBJECTIVES

To derive a new horizontal plane which can be a suitable alternative to Frankfurt horizontal plane (FH plane).

MATERIALS AND METHODS

200 pre-treatment lateral roentogenic cephalograms from patient records in the department of orthodontics and dentofacial orthopaedics were traced. The landmarks were identified and marked and the measurements were carried out. Patients with all skeletal relationships were included in the study. The angle formed between the lines connecting anatomic porion, orbitale and machine porion was measured and tabulated. Dimorphism between the genders if any was also evaluated.

RESULTS

The mean angulation between the planes from the anatomic porion to orbitale to machine porion (PoA-Or-PoM) in our sample is 3.14 ± 2.17°. PoA to Or to PoM angulation for males is 2.57° and for females is 3.4°.

CONCLUSIONS

SIDS plane also called as derived FH plane given here is a reliable and easily reproducible alternative to the FH plane.

Digital evaluation and correlation of facial growth patterns assessed on lateral CEPH and orthopantomogram through ONECEPH mobile application

OBJECTIVES

This study aimed to investigate the correlation of gonial angle and three linear measurements on OPG and lateral cephalograms and their effects on the different facial patterns using the OneCeph android app.

METHOD

About 90 pre-treatment digital lateral cephalograms and OPGs of 90 patients were selected and divided into 3 categories, based on their growth patterns. The OPGs and lateral cephalograms were uploaded on the OneCeph android app. After calibrating using One linear measurement i.e. length of extracted premolar for OPG and ruler in radiograph for lateral cephalogram, Gonial angle (Ar- Go-Me), ANS-Me (LAFH), U1-NF, L1-MP were measured. The data were collected, tabulated, and subjected to statistical analysis using the SPSS software (version 20.0). The level of significance was kept at 5%.

RESULTS

Values for parameters were highest in the vertical growth pattern followed by average and horizontal in both cephalogram and OPG. Upon comparison of lateral cephalogram and OPG, no significant difference was observed in gonial angle and a significant difference in LAFH and L1-MP in all three growth patterns with OPG scores greater than cephalometric tracing. The interclass coefficient test indicated almost perfect agreement for the gonial angle between the two methods. A substantial agreement was seen for U1-NF on lateral cephalogram and OPG in the vertical group. Also, a fair agreement in the vertical and horizontal group was observed in Lower anterior mandibular height.

CONCLUSION

Vertical parameters such as gonial angle and maxillary anterior dental height can be accurately determined on an OPG by the OneCeph application.

Reliability of Photogrammetric Landmarks to the Conventional Cephalogram for Analyzing Soft-Tissue Landmarks in Orthodontics

Background

Graber introduced facial photographs as an internal diagnostic aid. Facial photographs could serve as an important alternative assessment tool in the absence of equipment for cephalometric analysis.

Objectives

The present study was aimed at assessing whether analyzing the photographs could have precision for assessing the landmarks appropriate for facial analysis. In addition, the relationship between frontal cephalogram and measurements on photographs was assessed.

Materials and Methods

Twenty individuals including both males and females within the age range of 18 years to 28 years were enrolled in the study. Frontal facial photographs, as well as frontal cephalograms, were obtained for all the included study participants. Various soft-tissue vertical and horizontal landmarks were marked on both radiographs and photographs. The data were collected and subjected to statistical analysis.

Results

The results showed a statistically insignificant difference between all the vertical and horizontal parameters on photographs and cephalograms. The reliability of the digital photographs was comparable to that of the cephalograms with nonsignificant differences in the recorded mean values using the one-way ANOVA test where the statistical significance level was kept at P ≤ 0.05.

Conclusion

The present study concluded that photography is a cost-effective and reliable method for soft-tissue landmark identification, and allows recording the images of sufficient quantity for analysis. Low-cost and easily captured photographic images can replace costly radiographic procedures without causing any discomfort to the patients.

Deep learning based prediction of necessity for orthognathic surgery of skeletal malocclusion using cephalogram in Korean individuals

BACKGROUND

Posteroanterior and lateral cephalogram have been widely used for evaluating the necessity of orthognathic surgery. The purpose of this study was to develop a deep learning network to automatically predict the need for orthodontic surgery using cephalogram.

METHODS

The cephalograms of 840 patients (Class ll: 244, Class lll: 447, Facial asymmetry: 149) complaining about dentofacial dysmorphosis and/or a malocclusion were included. Patients who did not require orthognathic surgery were classified as Group I (622 patients-Class ll: 221, Class lll: 312, Facial asymmetry: 89). Group II (218 patients-Class ll: 23, Class lll: 135, Facial asymmetry: 60) was set for cases requiring surgery. A dataset was extracted using random sampling and was composed of training, validation, and test sets. The ratio of the sets was 4:1:5. PyTorch was used as the framework for the experiment.

RESULTS

Subsequently, 394 out of a total of 413 test data were properly classified. The accuracy, sensitivity, and specificity were 0.954, 0.844, and 0.993, respectively.

CONCLUSION

It was found that a convolutional neural network can determine the need for orthognathic surgery with relative accuracy when using cephalogram.

Sella Turcica Area and Location of Point Sella in Cephalograms Acquired with Simulated Patient Head Movements

AIM AND OBJECTIVE

This study assesses changes in the sella turcica area (STA) and location of the cephalometric point sella (S) on lateral cephalograms acquired by charge-coupled device (CCD)-based cephalostats with and without simulated patient head movements.

MATERIALS AND METHODS

A real skull was placed on a robot, able to simulate four head movements (anteroposterior translation/lifting/nodding/lateral rotation) at three distances (0.75/1.5/3 mm) and two patterns (returning to 0.5 mm away from the start position/staying at maximum movement excursion). Two ProMax-2D cephalostats (Dimax-3, D-3 or Dimax-4, D-4), and an Orthophos-SL cephalostat (ORT) acquired cephalograms during the predetermined movements ("cases," 48 images/unit) and without movement ("controls," 24 images/unit). Three observers manually traced the contour of sella turcica and marked point sella using a computer mouse. STA was calculated in pixels² by dedicated software based on the tracing. S was defined by its x and y coordinates recorded by the same software in pixels. Ten percent of the images were assessed twice. The difference between cases and controls (case minus control) for the STA and S (namely Diff-STA and Diff-S) was calculated and assessed through descriptive statistics.

RESULTS

Inter- and intraobserver agreement ranged from moderate to good for STA and S. Diff-STA ranged from -42.5 to 12.9% (D-3), -15.3 to 9.6% (D-4), and -25.3 to 39.9% (ORT). Diff-S was represented up to 50% (D-3), 134% (D-4), and 103% (ORT) of the mean sella turcica diameter in control images.

CONCLUSION

Simulated head movements caused significant distortion in lateral cephalograms acquired by CCD-based cephalostats, as seen from STA and S alterations, depending on the cephalostat.

CLINICAL SIGNIFICANCE

Patient-related errors, including patient motion artifacts, are influential factors for the reliability of cephalometric tracing.

Nasopharyngeal structure development in patients with cleft palate who underwent repair surgery

OBJECTIVE

This study aimed to compare the developmental characteristics of bony nasopharyngeal (NP) in children with cleft palate (CP) and non-cleft subjects.

METHODS

This study was conducted on 64 non-syndromic CP patients who underwent repair surgery and 23 non-cleft subjects as controls. Lateral cephalograms were performed on participants at rest in the natural head position. The X-coordinate and the Y-coordinate of three points on cephalograms were determined as Hormion (Ho), posterior maxillary point (PMP) and anterior point of the atlas (At) representing the anterior-posterior (AP) and vertical dimension of the NP. The linear dimension of the NP (i.e. Ho-At, Ho-PMP, At-PMP) and its area was also calculated.

RESULTS

The bony structures of NP in the clef-affected subjects in isolated CP subgroup, had a significantly greater downward development in the maxillary region (PMP) (both with p = 0.001), more linear growth in cranial-maxillary (Ho-PMP) dimension (p = 0.017 and 0.004, respectively), and larger area (p = 0.017 and <0.001, respectively), when compared to normal subjects. There was no significant difference between either the unilateral cleft lip and palate (CLP) or bilateral CLP group with the control group regarding AP, vertical, and linear growth of the NP and its area (P > 0.05).

CONCLUSIONS

Patients with repaired CP had downward deviated posterior maxilla, more linear growth in cranial-maxillary dimension and larger area compared to normal subjects. Among CP subtypes, a balanced growth was observed among repaired UCLP and BCLP patients, suggesting that with appropriate repaired surgery, normal development of the NP region could be expected in these subtypes.

Study of soft tissue changes in the upper lip and nose after backward movement of the maxilla in orthognathic surgery

Objectives

This study evaluates soft tissue changes of the upper lip and nose after maxillary setback with orthognathic surgery such as Le Fort I or anterior segmental osteotomy.

Materials and Methods

All 50 patients with bimaxillary protrusion and skeletal Class II malocclusion underwent Le Fort I or anterior segmental osteotomy with backward movement. Soft and hard tissue changes were analyzed using cephalograms collected preoperatively and 6 months postoperatively.

Results

Cluster analysis on the ratios shows that 2 lines intersected at 4 mm point. Based on this point, we divided the subjects into 2 groups Group A (less than 4 mm, 27 subjects) and Group B (more than 4 mm, 23 subjects). Also, each group was divided according to changes of upper incisor angle (≥4°=A1, B1 or <4°=A2, B2). The correlation between A and B groups for Aʼ/ANS and Ls/Is (P<0.001) was significant; Aʼ/A (P=0.002), PRN/A (P=0.043), PRN/ANS (P=0.032), and St/Is (P=0.010). Variation of nasolabial angle between the two groups was not significant. There was no significant correlation of vertical movement and angle variation.

Conclusion

The ratio of soft tissue to hard tissue movement depends on the amount of posterior movement in the maxilla, showing approximately two times higher rates in most of the midface when posterior movement was greater than 4 mm. The soft tissue changes caused by posterior movement of the maxilla were little affected by angular changes of upper incisors. Interestingly, nasolabial angle showed a different tendency between A and B groups and was more affected by incisal angular changes when horizontal posterior movement was less than 4 mm.

A Formula for Estimating the Appropriate Tube Depth for Intubation

An estimation of the appropriate tubing depth for fixation is helpful to prevent inadvertent endobronchial intubation and prolapse of cuff from the vocal cord. A feasible estimation formula should be established. We measured the anatomical length of the upper-airway tract through the oral and nasal pathways on cephalometric radiographs and tried to establish the estimation formula from the height of the patient. The oral upper-airway tract was measured from the tip of the incisor to the vocal cord. The nasal upper-airway tract was measured from the tip of the nostril to the vocal cord. The tracts were smoothly traced by using software. The length of the oral upper-airway tract was 13.2 ± 0.8 cm, and the nasal upper-airway tract was 16.1 ± 0.9 cm. We found no gender difference ( p > .05). The correlations between the patients' height and the length of the oral and nasal upper-airway tracts were 0.692 and 0.760, respectively. We found that the formulas (height/10) - 3 (in cm) for oral upper-airway and (height/10) + 1 (in cm) for nasal upper-airway tract are the simple fit estimation formulas. The average error and standard deviation of the estimated values from the measured values were 0.50 ± 0.66 cm for the oral tract and 0.39 ± 0.63 cm for the nasal tract. Thus, considering the length of the intubation marker of each product (DM), we would like to propose the length of tube fixation as (height/10) + 1 + DM for nasal intubation and (height/10) - 3 + DM for oral intubation. In conclusion, the estimation formulas of (height/10) - 3 + DM and (height/10) + 1 + DM for oral and nasal intubation, respectively, are within almost 1 cm error in most cases.

Reliability of lateral cephalometric radiographs in the assessment of the upper airway in children: A retrospective study

OBJECTIVES

To test the reliability of Lateral cephalometric radiographs (LCRs) for use in the assessment of the upper airway, hyoid bone, soft palate, and tongue.

MATERIALS AND METHODS

The records of 57 healthy Chinese children from a nonhospital population (mean age = 12.6 years, SD = 0.5, 28 males and 29 females) who received two consecutive LCRs in the natural head posture were retrospectively analyzed. Fifteen linear, angular, and area measurements were used to describe the airway, hyoid bone, soft palate, and tongue. The reliability between the two LCRs was assessed with the intraclass correlation coefficient (ICC) and F-test. Errors were estimated with the Dahlberg and Bland-Altman method, and intra- and inter-assessor agreements were determined.

RESULTS

Measurements of upper airway and hyoid bone had excellent method reliability, intra-assessor reliability, and inter-assessor reliability (ICC > 0.8). However, the method reliability and the inter-assessor reliability for soft palate and tongue was less favorable (ICC from 0.60 to 0.96). Soft palate area and thickness were the most critical parameters. Intra-assessor reliability was greater than both method reliability and inter-assessor reliability (which were similar).

CONCLUSIONS

The measurement of upper airway morphology, defined as the intramural space, and of the hyoid bone position were highly reliable on LCRs of children. However, the limited reliability in the assessment of tongue and soft palate area may compromise the diagnostic application of LCRs to these structures.

Accuracy of lateral cephalogram for diagnosis of adenoid hypertrophy and posterior upper airway obstruction: A meta-analysis

INTRODUCTION

Accurate diagnosis of adenoid hypertrophy and posterior upper airway obstruction using a lateral cephalogram is challenging. No universal guidelines for assessing adenoidal enlargement and upper airway obstruction have been established. We performed a meta-analysis to assess the diagnostic accuracy of a lateral cephalogram for adenoid hypertrophy.

METHODS

After searching a wide range of electronic databases and screening titles and abstracts, we evaluated full papers describing potentially eligible studies according to predefined inclusion criteria. Quality assessment was conducted by adapting the Quality Assessment of Diagnostic Accuracy Studies-2 checklist, and a 2 × 2 contingency table was constructed based on these results. Two authors independently judged the studies and extracted the data. The diagnostic accuracy of a lateral cephalogram for adenoid hypertrophy and posterior upper airway obstruction was calculated using a bivariate meta-analysis model. The Q-test and I² index were used to test the heterogeneity.

RESULTS

Nine studies were included in the meta-analysis. The pooled sensitivity, specificity, diagnostic odds ratio, positive likelihood ratio, and negative likelihood ratio were 0.86 [95% confidence interval (CI): 0.76-0.92], 0.59 (95% CI: 0.42-0.73), 9.00 (95% CI: 5-17), 2.1 (95% CI: 1.5-3.0), and 0.24 (95% CI: 0.15-0.37), respectively. The area under the summary receiver operator characteristic curve was 0.83 (95% CI: 0.80-0.86). Meta-regression analysis revealed that the sample size and study design significantly contributed to the heterogeneity of sensitivity.

CONCLUSIONS

Our findings suggest that the lateral cephalogram exhibits very good diagnostic accuracy (area under the curve: 0.86) for the diagnosis of adenoid hypertrophy and posterior upper airway obstruction. Nevertheless, the rate of false-positive diagnoses should be further considered.

Comparison of upper airway measurement by lateral cephalogram in upright position and CBCT in supine position

Background/Purpose

Obstructive sleep apnea syndrome (OSAS) is a common form of sleep disorder. Lateral cephalograms and cone-beam computed tomography (CBCT) have been used for evaluation. However, it is lack of position comparison for these two assessments. Therefore, this study was aimed to evaluate the difference of upper airway measurements taken from lateral cephalograms in upright position and CBCT in supine position.

Material and methods

This retrospective study enrolled patients with lateral cephalograms and CBCT images due to diagnostic necessity. The anterior-posterior distance of most constricted area in pharynx (PASmin) and the distance from mandibular plane to hyoid bone (MP-H) were identified and measured from 21 normal subjects without obstructive sleep apnea (9 males and 12 females, mean age 21.2 years). A paired data were measured from lateral cephalograms taken in upright position and lateral cephalometric images derived from CBCT taken in supine position. Both images were taken within two months. All data were analyzed statistically.

Results

No significant difference was identified in intra-examiner reliability (P > 0.05). PASmin measured from lateral cephalograms in upright position was larger than that taken from CBCT derived cephalometric images, but without statistical significant difference (P = 0.073). Significant difference of MP-H length was identified between two different image taking methods (P = 0.000), and the measurement was significantly larger in cephalograms taken from upright position. No correlations were found among the variables (Body Mass Index (BMI), age, gender) in this study. The only two variables correlated were PASmin and MP-H, and they were negatively correlated (r = −0.535).

Conclusion

The anterior-posterior distance of most constricted area in pharynx (PASmin) and distance of mandibular plane to hyoid bone (MP-H) can be influenced due to change of body position.

Changes in Soft Tissue Profile After Orthodontic Treatment With and Without Extraction: A Systematic Review and Meta-analysis

OBJECTIVE

The objective of this systematic review and meta-analysis was to evaluate the soft tissue changes in adult orthodontic patients who received extraction treatment in comparison to their counterparts who received nonextraction orthodontic treatment.

METHODS

Electronic databases (CENTRAL-Cochrane Register of Controlled Trials, PubMed, Embase, EBESCOhost, LILACS, and Google Scholar) were searched up to March 2015. Handsearching was performed too. The selection process included controlled trials (prospective or retrospective and randomized or nonrandomized) on adult patients receiving orthodontic extraction treatment compared within the same study to a group treated without extraction. The outcomes of interest were the changes in linear and angular cephalometric measurements specific for soft tissue profile. Studies which fulfilled the selection criteria were retrieved. They were assessed for methodological quality based on a validated checklist. Studies of moderate to high quality were included.

RESULTS

Of the nine full texts which fulfilled the selection criteria, 5 were eligible for the quantitative analysis; they scored a moderate quality. Meta-analysis showed a significant increase regarding the nasolabial angle, upper lip thickness, labrale superioris to E-Line, and labrale inferioris to E-line in the extraction group, suggesting the flattening of the profile following extraction treatment.

CONCLUSION

A significant retraction of the lips and an increase in the nasolabial angle are associated with extraction protocols, but the degree to which these changes are considered detrimental/beneficial to the profile could be affected by different factors. Since these finding are based on studies of moderate quality, future research with well-conducted methodologies are highly recommended.

Evaluation of Predictability of Suitable Implant Lengths as related to Accurate Treatment Planning using Recent Roentgenographic Measures: A Key to Success

BACKGROUND AND AIM

Selection of suitable length of dental implants is very subjective and largely depends on clinical evidences and operator's expertise. The present study was aimed to assess the role of cone beam computed tomography (CBCT) and cephalograms as far as the selection of right implant length is concerned.

MATERIALS AND METHODS

The study includes 220 patients for whom radiographic and follow-up records were obtained. There were 105 males and 115 females in the age range of 22 to 58 years. A total of 98 implant sites in different edentulous areas were studied. Length of implant was predicted at treatment planning and compared with finally placed implant at surgical stages. It also includes the in-depth exploration of (1) number of implants placed per patient, (2) implant per edentulous areas, (3) implant location, and (4) implant region. For prediction of implant lengths, CBCT results were obtained and compared with cephalometric findings. Accuracies of implant lengths as planned by CBCT and cephalometric images were also studied at treatment planning and surgical stages. Statistical analysis and results: Upon statistical comparisons, we found that larger implant lengths chosen at treatment planning stage did not change in 65.5% of patients. In addition, the smaller length implants were just about the same as that with larger dimensions. The CBCT results were satisfactory (up to 98.5%). Cephalometry was performed well in this prediction, especially in posterior mandible (87.9%). However, its performance in anterior maxillary region was not satisfactory (69.6%). Intergroup comparisons of CBCT and cephalometric results at different regions were significant (p < 0.001).

CONCLUSION

Our study results show insignificant changes in the length of implants that was exactly planned using CBCT scans. Therefore, accurate prediction of implant lengths can be done using CBCT scans as they have superior and advanced tools that facilitate presurgical decision-making. Lateral cephalometric evaluation has been shown as an imperative radiographic tool for determining implant lengths as it confirmed the significance bone resorption on the selection of implant length at different sites.

CLINICAL SIGNIFICANCE

The CBCT and lateral cephalogram offer excellent anatomical details that can be judiciously applied for treatment planning and other clinical decision-making, including selection of correct implant length. Our study advocates thorough cephalometric evaluations of mandible wherein implants are to be placed for implant-supported overdentures.

Association between skeletal morphology and agenesis of all four third molars in Japanese orthodontic patients

The purpose of this study was to clarify differences in skeletal morphologies between male and female orthodontic patients with and without agenesis of all four third molars. A total of 64 patients (32 males and 32 females) with agenesis of all four third molars without agenesis of other teeth were selected as the third molars agenesis group (group 1). In addition, 64 patients (32 males and 32 females) with all these teeth were selected as controls (group 2). Lateral cephalograms taken between the ages of 14 and 30 years were used to compare skeletal morphology between groups 1 and 2 and between sexes. Maxillary length (P < 0.001), lower facial height (P < 0.05), gonial angle (P < 0.001) and mandibular plane angle (P < 0.001) were significantly smaller in group 1 than in group 2. Irrespective of the presence or absence of all four third molars, males had significantly smaller lower facial height (P < 0.01) and mandibular plane angle (P < 0.001) and significantly greater total mandibular length (P < 0.001), mandibular body length (P < 0.001) and mandibular ramus height (P < 0.001) than females. Japanese orthodontic patients with agenesis of all four third molars had significantly small maxillary length, lower facial height, gonial angle and mandibular plane angle.

Evaluation of Mandibular Condylar Changes in Patients Following Orthognathic Surgery: A Retrospective Study

BACKGROUND

Condylar resorption as a cause of relapse after orthognathic surgery is well known. Several authors have presented evidence of the relation between orthognathic surgery and condylar remodeling and resorption. This study was done to appraise the condylar changes along with the form and function following orthognathic surgery, as well as to assess what factors may have contributed to the problems.

METHODOLOGY

A diagnosis of progressive condylar resorption (PCR) was made by comparison of preoperative and postoperative radiographs (cephalometric radiograms), as well as clinical evaluations. The radiographs were taken for each patient preoperatively and postoperatively, which include immediately after osteotomy, at 6 months and 24 months. Additional radiographs were taken when required. Then, preoperative and postoperative tracings were compared at 24 months postoperatively.

RESULTS AND CONCLUSION

It can be concluded from this study that females of relative low age (<18 years) appeared to be a high-risk factor for the occurrence of condylar alteration including PCR. A steep mandibular plane angle, the low facial height ratio (post/ant), and magnitude of surgery were also significantly related to the occurrence of condylar alteration, but the multivariance regression showed that these parameters had only limited value.

Dentoskeletal and Soft Tissue Effects in the Treatment of Class II Malocclusion with Klammt's Elastic Open Activator

AIM

The purpose of this study was to evaluate the dentoskeletal and soft tissue effects resulting from treatment with Klammt's elastic open activator (EOA) functional orthopedic appliance in patients with Class II malocclusion characterized by mandibular deficiency.

MATERIALS AND METHODS

Teleradiographs were evaluated in the lateral aspect of the initial (T1) and final (T2) orthopedic phases for 16 patients with Class II, Division 1 malocclusion. The age range was from 9 to 11.2 years, with a mean age of 9.9 years. The cephalometric points were demarcated, and cephalometric measurements were obtained by the same investigator to avoid interobserver variability.

RESULTS

The EOA promoted increased lower anterior facial height (LAFH), increased effective mandibular length, clockwise rotation of the mandible, retrusion and verticalization of the upper incisors, proclination and protrusion of the lower incisors, extrusion of the upper molars, mesial movement of the lower molars and anterior projection of the lower lip.

CONCLUSION

Skeletal changes characterized by an increase in mandibular length and dentoalveolar changes with an emphasis on the verticalization and retrusion of the upper incisors, proclination of the lower incisors and mesial positioning of the lower molars were key to improving the occlusal relationship and esthetic facial factors.

CLINICAL SIGNIFICANCE

The EOA is well indicated in patients with Class II malocclusion due to mandibular deficiency with increased overbite, proclined upper incisors and verticalized lower incisors.

Analysis of Pharyngeal Airway Using Lateral Cephalogram vs CBCT Images: A Cross-sectional Retrospective Study

Background : As the basic biological relationship of form and function, changes in the normal pattern of nasopharyngeal space can profoundly affect the development of the craniofacial growth. The lateral cephalogram, part of the patient’s normal records for orthodontic treatment, may show some of these changes either at the initial examination or later during treatment. The validity of the information the lateral cephalogram may present, have been questioned previously. The aim of this study was to assess correlation between the area and the volume measurements of pharyngeal airway size in a lateral cephalogram and a 3-dimensional (3D) cone-beam computed tomography (CBCT) scan in adolescent subjects. Materials and Methods : CBCT scan and a lateral cephalogram of 35 subjects which were taken within 1 week were included in this study. Airway area of the region of interest from the lateral cephalogram and airway volume over the same of region of interest from the CBCT scan were assessed for all patients. The correlation between the area and the volume measurements were evaluated statistically by Pearson’s correlation coefficient test. Mann Whitney U Test was used for comparing the area and the volume measurements in different sex. Results : Strong correlation was found between lateral cephalogram and CBCT measurements of pharyngeal airway. (r=0.831). Conclusion : Pharyngeal airway area on a lateral cephalogram is correlated strongly with volumetric data on CBCT images. Henceforth the use of CBCT images for volume measurements in orthodontic patients can aid in the better evaluation of airways and acted as a diagnostic instrument in this area.

Comparison of gonial angle determination from cephalograms and orthopantomogram

Introduction:

Gonial angle is an important parameter of the craniofacial complex giving an indication about the vertical parameters and symmetry of the facial skeleton. Both orthopantomogram (OPG) and lateral cephalograms can be used for the measurement of gonial angle. Because of the superimpositions seen on lateral cephalograms, reliable measurement of the gonial angle becomes difficult. The aim of the present study is to check the possible application and reliability of OPG for gonial angle determination by clarifying whether there is any significant difference between the determination of gonial angle from OPG and cephalogram.

Materials and Methods:

Gonial angle measurements were made on lateral cephalograms and orthopantomograms of 98 patients - 44 males (mean age 25.9 years) and 54 females (mean age 21.3 years), and compared using Statistical Package for Social Sciences.

Results:

One-way analysis of variance demonstrated no significant differences between the values of gonial angles determined by lateral cephalogram and panoramic radiography. Pearson correlation showed a high correlation between cephalometric and OPG gonial angle value.

Conclusion:

Panoramic radiography can be used to determine the gonial angle as accurately as a lateral cephalogram. For determination of the gonial angle, an OPG may be a better choice than a lateral cephalogram as there are no interferences due to superimposed images of anatomical structures as in a lateral cephalogram. Thus, the present study substantiates the possibility of enhancing the clinical versatility of the panoramic radiograph, which is an indispensable tool for dental diagnosis.

Recent advances in imaging technologies in dentistry

Dentistry has witnessed tremendous advances in all its branches over the past three decades. With these advances, the need for more precise diagnostic tools, specially imaging methods, have become mandatory. From the simple intra-oral periapical X-rays, advanced imaging techniques like computed tomography, cone beam computed tomography, magnetic resonance imaging and ultrasound have also found place in modern dentistry. Changing from analogue to digital radiography has not only made the process simpler and faster but also made image storage, manipulation (brightness/contrast, image cropping, etc.) and retrieval easier. The three-dimensional imaging has made the complex cranio-facial structures more accessible for examination and early and accurate diagnosis of deep seated lesions. This paper is to review current advances in imaging technology and their uses in different disciplines of dentistry.

Mandibular dimensional changes and skeletal maturity

AIM

Growth and development of the human face provides a fascinating interplay of form and function. Among the various facial bones, the mandible plays a very important role during various growth-modification therapies. These treatment modalities will yield a better result in less time if properly correlated with skeletal maturity. It is very essential to know where the site of growth occurs and also the time when it occurs or ceases to occur. This study was conducted to assess the mandibular dimensions at various stages of skeletal maturation.

MATERIALS AND METHODS

The subjects included 6 to 18-year-old children who were grouped according to their middle phalanx of the third finger stages of skeletal maturity. Lateral cephalographs were taken and, from their cephalometric tracings, linear and angular measurements of the mandible were made. The values obtained were subjected to statistical analysis.

RESULTS

Results showed that the mandibular height, length and symphysis thickness increased with skeletal maturity. An increase in angles SNB (Sella, Nasion, Supramentale) and L1-MP (Long axis lower incisors- Mandibular plane) and a decrease in the gonial angle and ANB (Subspinale, Nasion, Supramentale) angle were observed.

CONCLUSION

The study showed a significant correlation between mandibular growth and skeletal maturity.

A cephalometric study to determine the plane of occlusion in completely edentulous patients: part I

To determine the relationship between the plane of occlusion and the Camper's line (ala-tragus line). Lateral cephalograms of 105 dentulous subjects were obtained after outlining the tragus and the base of the ala of the nose with radiopaque markers. Tracings of the cephalograms were done and the relationship between the plane of occlusion and the Camper's line (ala-tragus line) was noted. The most common tragal reference as a posterior landmark for determination of plane of occlusion was found to be below inferior (in 30.48% of subjects), and inferior (in 24.76% of subjects). The least common tragal reference was found to be above superior (in 3.82% of subjects) followed by superior of tragus and the point between superior and middle of the tragus (in 6.66% of subjects). The tragal reference in this study population was more towards the inferior of the tragus, with most of the times being below the inferior border. Therefore, the orientation of the plane of occlusion using the superior of tragus as a posterior landmark (according to the widely accepted definition of Camper's line) may be considered to be questionable. Further, the use of the tragus as a posterior landmark for the orientation of the plane of occlusion may be questioned on the basis of the findings of this study.