Predictive Equation for Construction of Anatomic Porion with Machine Porion as Reference Point.

AIM: The aim of the study was to find a relationship between anatomic porion (PoA) and machine porion (PoM) and to construct PoA with the help of machine porion. METHODOLOGY: About 200 pretreatment lateral roentgenic cephalograms were used for the study. Perpendicular distances of PoA and PoM were measured from Sella-Nasion (SN) plane and SN perpendicular plane. The results were tabulated. With the help of statistical analysis, predictive equation was derived to construct PoA and PoM. p-value was set at p < 0.05. RESULTS: Anatomic porion distance from SN was 24.35 ± 3.96 and from SN perpendicular was 12.89 ± 4.56. Distance of PoM from SN was 22.46 ± 4.20 and from SN perpendicular was 16.76 ± 4.89. Sexual dimorphism was also seen. CONCLUSION: There is a relationship between the PoM and PoA, thus, PoA, which is more reliable, can be constructed with the help of PoM, which is easy to reproduce. CLINICAL SIGNIFICANCE: To overcome the inherent limitations of PoA and PoM, the present study aimed to find a relationship between the two so as to easily construct PoA that is more reliable while taking advantage of the ease of reproducibility of PoM.

Reliability of Frankfort Horizontal Plane with True Horizontal Plane in Cephalometric Measurements.

INTRODUCTION: The purpose of the study is to determine reliability of true horizontal (TH) plane with Frankfort horizontal (FH) plane in cephalometric measurements. MATERIALS AND METHODS: One hundred lateral cephalograms were collected and traced using FACAD software, all cephalometric measurements which included FH plane as reference planes were used in this study. Cephalometric tracing was done with FH plane as reference plane and another set of measurements with TH plane as reference plane was done. Statistical tests were done using independent sample t-test (p <0.05). RESULTS: Results of an independent t-test revealed a statistically insignificant difference that was observed for all the parameters assessed (p <0.05). Both angular and linear measurements showed an insignificant difference between FH and TH. CONCLUSION: Within the limitations of the study, the results show that the FH plane is closest and as reliable as the TH plane. The variation of FH was least for all the parameters assessed.

A clinico-radiographic study to compare and co-relate sagittal condylar guidance determined by intraoral gothic arch tracing method and panoramic radiograph in completely edentulous patients.

PURPOSE: The purpose of this study was to compare and correlate sagittal condylar guidance determined by intraoral gothic arch tracing method and panoramic radiograph in edentulous patients. MATERIALS AND METHODS: Twelve completely edentulous patients were selected by the inclusion and exclusion criteria. Conventional steps in the fabrication of complete denture till jaw relation were carried out. Intraoral gothic arch tracing and protrusive interocclusal records were obtained for each patient. Protrusive interocclusal record was used to program the Hanau Wide-Vue semi-adjustable articulator, thus obtaining the sagittal condylar guidance angle. Using RadiAnt DICOM software, on the orthopantomogram obtained for each patient in the study, two reference lines were drawn. The Frankfort's horizontal plane and the mean curvature line (joining the most superior and the inferior points on the glenoid fossa curvature) were drawn. The mean curvature line was extended to intersect the Frankfort's horizontal plane, thus obtaining the radiographic sagittal condylar guidance angle. The condylar guidance angles obtained by these two methods were compared and subjected to paired t-test. RESULTS: There was no statistically significant difference between the sagittal condylar guidance angles obtained between right and left sides with intraoral gothic arch tracing and radiographic methods (P = 0.107 and 0.07, respectively). CONCLUSION: Within the limitations of this study, it was concluded that the protrusive condylar guidance angles obtained by panoramic radiograph may be used for programming semi-adjustable articulators.

Evaluation of accuracy of transfer of the maxillary occlusal cant of two articulators using two facebow/semi-adjustable articulator systems: An in vivo study.

AIM: The aim of this study was to compare the accuracy of the angle made by Frankfort horizontal plane-occlusal plane on maxillary casts, mounted using the respective facebows on Artex Amann Girrbach and Hanau Wide-vue semi-adjustable articulators with cephalometrically derived Frankfort horizontal plane-occlusal plane angle as a control. SUBJECTS AND METHODS: Maxillary casts of 30 subjects were mounted on Hanau Wide-vue and Artex Amann Girrbach semi-adjustable articulators following facebow transfer using respective facebows. The Frankfort horizontal plane-occlusal plane angles of these casts were measured using Wixey's digital angle gauge. They were also subjected to a lateral cephalogram, and the occlusal cant was measured using RadiAnt DICOM software. STATISTICAL ANALYSIS: Using Pearson correlation, the accuracy of the angle made by upper member of the articulator and occlusal plane of mounted maxillary casts in each of the articulator was compared to the Frankfort horizontal plane-occlusal plane angle in lateral cephalogram. RESULTS: A mean difference of 1.9° was found between Hanau Wide-vue articulator and lateral cephalogram and a mean difference of 3.6° was found between Artex Amann Girrbach articulator and lateral cephalogram. Statistically, Pearson correlation value (r) obtained between Hanau Wide-vue and lateral cephalogram was 0.46 and between Artex Amann Girrbach and lateral cephalogram was 0.25. CONCLUSION: From the statistical value (r) derived, it can be inferred that the Frankfort horizontal plane-occlusal plane angle of the casts articulated on Hanau Wide-vue articulator was more accurate in comparison to that on Artex Amann Girrbach articulator.

Reliability of anatomic reference planes in establishing the occlusal plane in different jaw relationships: a cephalometric study.

The purpose of this study was to evaluate the reliability of different anatomic reference planes in determination of Occlusal plane in dentulous and edentulous subjects with Angle's class I and class II Maxillomandibular relationship. Eighty subjects were included in the study which was divided into four Groups based on dentition and skeletal relationship. The Group I (n = 20) and Group II (n = 20) includes young and completely dentulous subjects in Angle's class I and class II relationship, respectively. The Group III (n = 20) and Group IV (n = 20) subjects were completely edentulous in Angle's class I and class II relationship, respectively. For all subjects, right lateral cephalograms were taken and cephalometric analysis was done and data obtained from cephalometric tracings were then statistically analyzed. The results showed no significant difference of angle between Occlusal plane and Frankfort Horizontal plane, Camper's plane and Palatal plane when Group I and Group III, and Group II and Group IV subjects were compared. The Frankfort Horizontal plane, Camper's plane and the Palatal plane may be used as a reliable guide to establish Occlusal plane in edentulous subjects in both Angle's class I and class II Maxillomandibular relationships.

Comparison of accuracy of protrusive condylar guidance registration by two interocclusal recording materials in edentulous patients.

Background and Purpose: During complete denture fabrication making Interocclusal records plays an integral role to obtain the condylar guidance value. The study was conducted to compare the protrusive condylar guidance registration by two interocclusal recording materials-Quick setting plaster and Luxabite®(bisacrylic composite) in semi adjustable articulator for completely edentulous patients. Methodology: Maxillary and Mandibular casts of the completely edentulous patients were mounted in Hanau®Wide Vue articulator. The Quick setting plaster and Luxabite®(bisacrylic composite) was used as interocclusal recording materials to program the protrusive condylar guidance angles in the articulators. Results: The protrusive condylar guidance values registered in the articulator for the different interocclusal records were tabulated and statistically analyzed.. The mean protrusive condylar guidance values registered in the articulator was compared with two parameters obtained from the radiographic tracings -- the protrusive condylar path angle obtained with Quick setting plaster and Luxabite with the inclination of articular eminence to the Frankfort horizontal plane. Conclusion: From the study it was concluded that the Luxabite®(bisacrylic composite) material demonstrated better reproducibility of protrusive condylar guidance registration.than the Quick setting plaster.

Résumé Contexte et objectif: Pendant la fabrication complète de la prothèse de prothèse, la fabrication des enregistrements d'interoccluse joue un rôle essentiel pour obtenir la valeur de guidage condylien. L'étude a été réalisée pour comparer l'enregistrement de guidage condylien en saillie par deux matériaux d'enregistrement interocclusal - Platter en plâtre et Luxabite® (composite bisacrylique) dans un articulateur semi-réglable pour les patients complètement édentés. Méthodologie: Les moulages maxillaires et mandibulaires des patients complètement édentés ont été montés dans l'articulateur de Hanau® à large de Vue. Le plâtre à réglage rapide et Luxabite® (composite bisacrylique) ont été utilisés comme matériel d'enregistrement interocclusal pour programmer les angles de guidage condyliennes en saillie dans les articulateurs. Résultats: Les valeurs de guidage condylien en saillie enregistrées dans l'articulateur pour les différents enregistrements interocclusaux ont été tabulées et analysées statistiquement. Les valeurs de guidage condyliennes en protruments moyennes enregistrées dans l'articulateur ont été comparées à deux paramètres obtenus à partir des tracages radiographiques - le protruments de l'angle de trajectoire condylien obtenu avec un plâtre rapide et luxabite avec l'inclinaison d'une éminence articulaire au plan horizontal de Frankfort. Conclusion: D'après l'étude, il a été conclu que le matériau Luxabite® (composite bisacrylique) avait démontré une meilleure reproductibilité de l'enregistrement de guidage condylien en saillie que le plâtre de réglage rapide. Mots-clés: Guidage condylien, édenté, facebow, plan horizontal de Frankfort, dossier interocclusal, radiographie céphalométrique latérale, guidage condylien en saillie, articulateur semi-réglable.

Diagnostic validity of different gonial angle segmentation for the assessment of mandibular growth direction: A retrospective study.

BACKGROUND: The development of the mandible largely determines the sagittal and vertical lateral appearance. The gonial angle (Articulare-Gonion-Menton, Ar-Go'-Me), as a composite indicator, represents the growth direction of the mandible. We proposed a method based on the Frankfort horizontal (FH) plane and its vertical plane (VFH) to divide the gonial angle into sagittal and vertical components (Articulare-Gonion-VFH / Menton-Gonion-FH, Ar-Go'-VFH / Me-Go'-FH) and to compare the accuracy of diagnosing the development of the mandible and maxillofacial structures with other methods. METHODS: Lateral cephalometric films from 736 volunteers aged 6-30 years were collected and analyzed for cephalometric measurements. Four groups of segmentation-based angle, including the FH-based segmentation (Ar-Go'-VFH / Me-Go'-FH), the SN-based segmentation (Articulare-Gonion- Sellion-Nasion plane' vertical plane/ Menton-Gonion- Sellion-Nasion plane, Ar-Go'-VSN / Me-Go'-SN), the Go'-S based segmentation(Articulare-Gonion-Sellion / Menton-Gonion-Sellion, Ar-Go'-S / Me-Go'-S), and the Go'-N based segmentation (Articulare-Gonion-Nasion / Menton-Gonion-Nasion, Ar-Go'-N / Me-Go'-N), as well as commonly used sagittal and vertical indices were measured. Pearson correlation analysis was used to show the representativeness of different segmentation methods on the mandibular growth direction. RESULTS: As the gonial angle decreased with age, all the segmentation-based metrics decreased. The plane-based segmentation metrics, including Ar-Go'-VFH / Me-Go'-FH, Ar-Go'-VSN / Me-Go'-SN, were superior to the point-based segmentation metrics (Ar-Go'-S / Me-Go'-S, and Ar-Go'-N / Me-Go '-N) in evaluating vertical and sagittal development of the mandible. The sagittal indicators displayed alteration of ramus and condyle, while these vertical indicators responded to the alteration of the mandibular corpus and gonial angle. CONCLUSIONS: The gonial angle should be clinically segmented with planes (including SN plane and FH plane) rather than points (including Go'-S and Go'-N) to assess mandibular development. The FH plane-based segmentation method facilitated chair-side diagnosis of the mandibular growth direction.

Role of Plain Radiographs in Assessing Appropriate Placement of Orbital Implants for Repair of Floor Fractures.

Intraoperative imaging is becoming increasingly common in repair of facial fractures. Many institutions do not have access to intraoperative advanced 3D imaging but have the capability of obtaining plain radiographs intraoperatively. At institutions where advanced 3D imaging is available, scout radiographs are usually obtained prior to a complete scan. These scout images can provide some information about the placement of radiopaque implants before a complete scan is performed. The aim of this study is to examine the correct anatomic positioning of an orbital floor implant using lateral plain radiographs. Titanium orbital fan implants were molded and secured to orbital floor of 14 adult dry skulls (7 males and 7 females). Lateral radiographs were obtained for both the left and the right orbits individually. The antero-posterior angle of inclination that the implant makes relative to the Frankfort horizontal plane was measured, and results were compared in the male versus female radiographs. The mean angle that the implant made with the Frankfort horizontal plane was 20.1±2.4° in the male orbits (95% CI 18.8-21.5°) and 22.6 ± 2.0° in the female orbits (95% CI, 21.4-23.7°). We found no statistically significant differences between the male and female angles (P-value 0.62). For the combined specimens (i.e., 28 sides in 14 skulls), the overall mean angle was 21.4 ± 2.5° (95% CI, 20.4-22.3°). Based on these findings, the angle that the implant makes with the Frankfort horizontal plane on lateral cross-table plain radiographs can be used intraoperatively to assist the surgeon in confirming the appropriate placement of the implant.

Cephalometric Evaluation of Natural Head Position in Lingayat Population of Karnataka.

AIMS AND OBJECTIVES: To ascertain norms in cephalometry for 11- to 13-year-old Lingayat children in natural head position (NHP). MATERIALS AND METHODS: Lateral cephalograms of children were obtained by using fluid level device. We determined the variance in Frankfort horizontal plane (FHP) inclination to extracranial horizontal in NHP. The G*Power, version 20 for Windows was used for analysis. RESULTS: Reduced facial convexity was observed when the analysis was carried out in relation to true horizontal with significant difference of "t" value of 3.05 and percentage difference of 1.1 (P < 0.01) and for girls "t" value of 9.69 and percentage difference of 2.5 (P < 0.001). The highest correlation coefficient for Lingayat boys (r = 0.77) was seen between palatal plane and occlusal plane. We found least correlation coefficient among FHP and Sella-nasion plane (SNP). The coefficient was r = 0.62 and correlation coefficient of r = 0.70 was between FHP and determination coefficient r 2 = 0.38 or 38%. For girls, highest correlation coefficient of r = 0.70 was seen among FHP and palatal plane. CONCLUSION: Conventional study of craniofacial forms of Lingayat children showed the average skeletal pattern as Class II with retrognathic mandible in comparison to Caucasians. However, when seen in NHP by new method of analysis based on the true horizontal, the skeletal model was Class III in comparison to Caucasians.

A cephalometric study to establish the relationship of the occlusal plane to the three different ala-tragal lines and the Frankfort horizontal plane in different head forms.

BACKGROUND: The aim of the study is to compare the relationship of the occlusal plane to 3 different ala-tragal lines, namely the superior, middle and inferior lines, in individuals having different head forms and its relation to the Frankfort horizontal plane. METHODOLOGY: A total of 75 lateral cephalometric radiographs of subjects with natural dentition, having full complement of teeth, between the age group of 18-25 were screened and selected. Lateral cephalogram were made for each subjects in an open mouth position. Prior to making the lateral cephalogram, radiopaque markers were placed on the superior, middle and inferior tragus points and on the inferior border of the ala of the nose. Cephalometric tracing was done over each cephalogram. RESULTS: In mesiocephalic head form the middle ala-tragal line was most parallel to the occlusal plane having a mean angle of (1.96°). In dolichocephalic headform, the superior ala-tragal line was most parallel to the occlusal plane having a mean angle of (0.48°). In brachycephalic head form, the middle ala-tragal line was most parallel to the occlusal plane having a mean angle of (2.08°). The mean angulations of occlusal plane to FH plane is 11.04°, 10.16° and 10.60° in mesiocephalic, dolichocephalic and brachycephalic head forms, respectively. RESULTS AND CONCLUSION: The study concludes that the middle ala-tragal line can be used as a reference for the mesiocephalic head form and the superior ala-tragal line for the dolichocephalic and brachycephalic head form as a reference to establish the occlusal plane.

A comparative study between data obtained from conventional lateral cephalometry and reconstructed three-dimensional computed tomography images.

OBJECTIVES: The aim of this study was to verify the concordance of the measurement values when the same cephalometric analysis method was used for two-dimensional (2D) cephalometric radiography and three-dimensional computed tomography (3D CT), and to identify which 3D Frankfort horizontal (FH) plane was the most concordant with FH plane used for cephalometric radiography. MATERIALS AND METHODS: Reference horizontal plane was FH plane. Palatal angle and occlusal plane angle was evaluated with FH plane. Gonial angle (GA), palatal angle, upper occlusal plane angle (UOPA), mandibular plane angle (MPA), U1 to occlusal plane angle, U1 to FH plane angle, SNA and SNB were obtained on 2D cephalmetries and reconstructed 3D CT. The values measured eight angles in 2D lateral cephalometry and reconstructed 3D CT were evaluated by intraclass correlation coefficiency (ICC). It also was evaluated to identify 3D FH plane with high degree of concordance to 2D one by studying which one in four FH planes shows the highest degree of concordance with 2D FH plane. RESULTS: ICCs of MPA (0.752), UOPA (0.745), SNA (0.798) and SNB (0.869) were high. On the other hand, ICCs of gonial angle (0.583), palatal angle (0.287), U1 to occlusal plane (0.404), U1 to FH plane (0.617) were low respectively. Additionally GA and MPA acquired from 2D were bigger than those on 3D in all 20 patients included in this study. Concordance between one UOPA from 2D and four UOPAs from 3D CT were evaluated by ICC values. Results showed no significant difference among four FH planes defined on 3D CT. CONCLUSION: FH plane that can be set on 3D CT does not have difference in concordance from FH plane on lateral cephalometry. However, it is desirable to define FH plane on 3D CT with two orbitales and one porion considering the reproduction of orbitale itself.

Systematic assessment of the various controversies, difficulties, and current trends in the reestablishment of lost occlusal planes in edentulous patients.

Accurate occlusal plane orientation is an essential factor in the fabrication of complete denture prosthesis. Over the years, it has received a number of methodologies by several researchers utilizing various anatomical landmarks however none of them is considered as perfect that could orient ideal occlusal plane. The presented literature review is an attempt to enlighten historical perspectives, pioneer researches, different controversies, difficulties and current trends for re-establishment of lost occlusal plane in edentulous patients. An extensive literature search was performed using Medline/PubMed interface and other scholarly research bibliographic databases using Medical Subject Headings. Studies describing research studies, case series and assorted clinical reports were retrieved and evaluated from 1963 to 2013. Most of the studies have suggest and evidence to consider Camper's plane for artificial orientation of occlusal plane however there is a substantial lack of genuine long term studies and authentic data that could recommend a single reliable landmark for perfect occlusal plane reorientation in a variety of cases.

Evaluation of the nasolabial angle of the Komarapalayam population.

Esthetic features are different from one race to another, and this should be considered during the treatment planning. The great variance in soft tissue drape of the human face complicates accurate assessment. The nose-lip-chin relationships are exceedingly important in determining the facial esthetics. One important soft tissue parameter in orthodontic diagnosis is the nasolabial angle. The purpose of this study was to establish norms for nasolabial angle as proposed by Fitzgerald for the Komarapalayam population. Normative data for the three nasolabial parameters were produced from a sample of 40 (20 male and 20 female) adults determined by the authors to have well-balanced faces. Mean and standard deviation values from this pooled sample demonstrated a lower border of the nose to Frankfort horizontal plane angle of 18° ± 7°, upper lip to Frankfort horizontal plane angle of 98° ± 5°, and nasolabial angle of 116° ± 10°. No statistically significant difference was demonstrated between the values for men and women in this study, but men did have a slightly larger nasolabial angle.