Different methods of determining centric relation - comparison with a digital mandibular motion analyser.

BACKGROUND: Finding and registering the maxillary-mandibular jaw relation is crucial in dental practice. Several comparative studies have been conducted to investigate the reproducibility and accuracy of techniques for determining the centric relation (CR) position of the mandible. The aim of our study was to determine which of seven different CR determination methods had the smallest deviation from the theoretical zero with the help of a digital mandibular motion analyser. The chosen theoretical zero position, the maximal intercuspal position (MIP), is the most reproducible and widely used position. METHODS: Thirty-four volunteers (24 females and 10 males) with a mean (SD) age of 29.1 (± 7.3) years with a negative history of temporomandibular disorder (TMD) participated in the study. A digital mandibular motion analyser was used to register the condylar position after the use of each technique for the determination of CR. The calibration was performed to the maximal intercuspal position (MIP) for each volunteer. The investigated techniques were (A) the gothic arch tracer, (B) the adduction field method, (C) Dawson's bimanual manipulation, (D) the patient placing the tongue tip on the palatal rugae, (E) the patient placing the tongue tip to the border of the hard and soft palate, (F) the patient actively pulling the chin backwards, and (G) the examiner pushing the patient's chin back. RESULTS: The position of the mandibular condyle was illustrated in a three-dimensional coordinate system, where the origin represented the MIP. Among the seven methods examined, five showed significant deviations compared to the MIP. Among these, two methods resulted in posterior deviation of the condyles. Methods C and E coincided with the MIP in all directions. CONCLUSIONS: Within the limitations of our study, we found that the smallest deviations from our theoretical zero (MIP) among the investigated centric relation determining methods were obtained with the bimanual mandibular manipulation technique derived from Dawson and the placement of the tongue tip on the border of the hard and soft palate (linguomandibular homotrophy theory).

[A clinical application study of digital manufacturing simple intraoral Gothic arch-tracing device in determining the centric relation of complete dentures].

OBJECTIVE: To verify the consistency between the digital manufacturing simple intraoral Gothic arch-tracing device and the traditional intraoral Gothic arch-tracing device in determining the centric relation of complete dentures restoration. METHODS: Ten outpatients with edentulous jaws were selec-ted, and the centric relation of the patients was determined by digital manufacturing of simple intraoral Gothic arch-tracing device (T1) and traditional intraoral Gothic arch-tracing device (T2); the difference of clinical operation time between the two methods was recorded; the upper and lower edentulous jaw plaster models were scanned with two kinds of centric relation, the Standard Triangle Language (STL) files imported into Geomagic studio software to apply the best fitting of multiple points of the both upper jaw models, the fitted STL files imported into the 3 shape viewer software, and the maximum position deviations of the vertical, labial (buccal) and lingual directions of the mandibular midline area and molar areas in T1 and T2 groups measured. During the clinical complete dentures try-in, we observed whether there was midline deviation in the mouth of T1 group and T2 group, and whether the occlusion of posterior teeth was stable or not. RESULTS: The mean time spent on determining the centric relation of T1 and T2 groups was (41.90±2.64) min, (57.50±2.37) min respectively. Paired t test was conducted in the two groups, P < 0.01 with significant statistical difference; The mean maximum position deviation between T1 group and T2 group of the midline mandibular region in labial lingual direction was (0.32±0.14) mm, that was (0.40±0.23) mm in vertical direction; the mean maximum position deviation of molar area in buccal lingual direction was (0.35±0.23) mm and that was (0.33±0.20) mm in vertical direction. In the vertical and horizontal directions, the maximum position deviation of mandibles between group T1 and group T2 was controlled within 0.5 mm. In the process of clinical complete dentures try-in, there was no deviation from the center line of dentures. There was not warping, swinging and other poor stability phenomena in T1 and T2 groups. CONCLUSION: The digital manufacturing of simple intraoral Gothic arch-tracing device can be used to determine the centric relation of complete dentures, which can not only save time of clinical operation, but also ensure the accuracy of the centric relation.

Indigenous digital intraoral Gothic arch tracer.

This paper describes indigenously developed digital Gothic arch tracer for the acquisition of centric jaw relation in patient. The developed tracer eliminates disadvantages of intra-oral tracing and makes it more suitable for recording centric relation in patients. The system also makes real-time monitoring of tracing possible in intraoral tracing. This also opens various avenues for research in removable prosthodontics.

Validity and reliability of intraoral conventional tracer and intraoral digital tracer in different positions for recording horizontal jaw relation in edentulous patients.

AIM: The purpose of the study is to evaluate and compare the horizontal mandibular positions recorded between intraoral conventional tracer and intraoral digital tracer in upright and supine position. MATERIALS AND METHODS: Twenty-four edentulous patients with well-formed ridge and adequate interarch distance space were selected. MATLAB software was assimilated with intraoral digital tracer and was utilized in the study for recording the horizontal movements of the mandible, i.e., gothic arch tracing by intraoral digital tracer and was observed on a laptop with the help of MATLAB Software. For each subject, multiple mandibular readings were recorded and analyzed through software, and similar readings were recorded with conventional intraoral tracers. The comparison between intraoral conventional tracer and intraoral digital tracer was done to assess the reliability. Moreover, the consistency of recording horizontal mandibular position was also compared between upright and supine position. RESULTS: The data were procured and utilized in comparison for different positions revealed statistically significant difference by using Student's Paired t-test. The test resulted in supine position better compared to upright position (P = 0.0001). The association between supine position with upright position was calculated using Fischer's exact test, and it was also found to be statistically significant (P = 0.002). The Pearson's Correlation analysis was performed to check the agreement between upright and supine position and very weak downhill correlation (r 2= -0.130) was observed between the two variables. CONCLUSION: On evaluation and comparison of horizontal mandibular position, it was found that the intraoral digital tracing technique is more valid compared to conventional intraoral tracer technique. It was also observed that the consistency of reproducibility in recording horizontal mandibular position in supine position is significantly higher than upright position.

Comparative Analysis of Sagittal Condylar Guidance Recorded by Intraoral Gothic Arch Tracing and Panoramic Radiograph in Completely Edentulous Patients.

AIM: To compare the intraoral gothic tracing method with panoramic radiographs in patients requiring complete dentures. MATERIALS AND METHODS: The present study was conducted on 20 edentulous subjects of both genders. Hanau Wide-Vue semi-adjustable articulator was used to record sagittal condylar guidance in all patients. Panoramic radiographs were taken in all patients and Frankfurt horizontal plane was traced on both sides of orthopantomogram (OPG) and second plane was marked by joining the most superior and most inferior point on the glenoid fossa curvature. Frankfort's horizontal plane was crossed with this line to record radiographic condylar guidance angle. NNT software was used to record the condylar guidance angle. RESULTS: Mean ± standard deviation (SD) clinical SCG (25.15 ± 3.24) and radiographic seismocardiography (SCG) (27.54± 5.01) was non significant (p > 0.05) on left side. Mean ± standard deviation (SD) clinical SCG (26.84 ± 3.69) and radiographic SCG (29.3 5 ± 4.58) was significant (p < 0.05) on right side. The SCG did not show difference in values recorded by both methods on both sides. The difference in values in both sides by clinical method and radiographic method was non-significant (p > 0.05). CONCLUSION: There was correlation between sagittal condylar guidance obtained by both intraoral gothic arch method as well as radiographic method done on digital panoramic radiographs. CLINICAL SIGNIFICANCE: Correct centric jaw relation determines the success of the complete denture. Radiographic and clinical methods provide sufficient minute details necessary for the betterment of management.

The Management of Aortic Coarctation Associated with Hypoplastic Arches and Particular Arch Anatomies: A Literature Review.

The surgical management of aortic coarctation in newborns needs to ensure postoperative evolution and long-term results as much as possible. Patients with a Gothic arch have a higher rate of postoperative hypertension, while newborns with a bovine arch have higher rates of restenosis and, thus, an additional risk of mortality. Late hypertension, even in anatomically successfully repaired patients, confers a high risk for cardiovascular events. This review of the literature focuses on the management of aortic coarctations associated with hypoplastic arch and particular arch anatomies, focusing on surgical techniques and their outcomes.

Using computed tomography angiography and computational fluid dynamics to study aortic coarctation in different arch morphologies.

Objective: To study the differences in computed tomography angiography (CTA) imaging of gothic arches, crenel arches, and romanesque arches in children with Aortic Coarctation (CoA), and to apply computational fluid dynamics (CFD) to study hemodynamic changes in CoA children with gothic arch aorta. Methods: The case data and CTA data of children diagnosed with CoA (95 cases) in our hospital were retrospectively collected, and the morphology of the aortic arch in the children was defined as gothic arch (n = 27), crenel arch (n = 25) and romanesque arch (n = 43). The three groups were compared with D1/AOA, D2/AOA, D3/AOA, D4/AOA, D5/AOA, and AAO-DAO angle, TAO-DAO angle, and aortic arch height to width ratio (A/T). Computational fluid dynamics was applied to assess hemodynamic changes in children with gothic arches. Results: There were no significant differences between D1/AOA and D2/AOA among gothic arch, crenel arch, and romanesque arch (P > 0.05). The differences in D3/AOA, D4/AOA, and D5/AOA among the three groups were statistically significant (P < 0.05), D4/AOA, D5/AOA of the gothic arch group were smaller than the crenel arch group, and the D3/AOA and D5/AOA of the gothic arch group were smaller than the romanesque arch group (P < 0.05). The difference in AAO-DAO angle among the three groups was statistically significant (P < 0.05), and the AAO-DAO angle of gothic arch was smaller than that of romanesque arch and crenel arch group (P < 0.05). There was no significant difference in the TAO-DAO angle between the three groups (P > 0.05). The difference in A/T values among the three groups was statistically significant (P < 0.05), and the A/T values: gothic arch > romanesque arch > crenel arch (P < 0.05). The CFD calculation of children with gothic arch showed that the pressure drop between the distal stenosis and the descending aorta was 58 mmHg, and the flow rate at the isthmus and descending aorta was high and turbulent. Conclusion: Gothic aortic arch is common in CoA, it may put adverse effects on the development of the aortic isthmus and descending aorta, and its A/T value and AAO-DAO angle are high. CFD could assess hemodynamic changes in CoA.

Treatment of acute type A aortic dissection with the Ascyrus Medical Dissection Stent in a consecutive series of 57 cases.

OBJECTIVES: The Ascyrus Medical Dissection Stent (AMDS) has been recently introduced as an alternative for total arch replacement in acute aortic dissection type A (AADA). The aim of this study was to evaluate the postoperative outcomes after AMDS treatment in a large contemporary cohort of AADA patients. METHODS: Data acquisition was performed retrospectively at 2 German aortic centres between 2020 and 2022 and comprised the perioperative parameters and postoperative results of all AADA patients. All patients treated with the AMDS for AADA were included in the study. The primary end point was in-hospital mortality. Secondary end points were defined as early postoperative and AMDS-related complications. RESULTS: Fifty-seven AADA patients treated by AMDS were included in the study group. The mean age was 64.6 ± 10.8 years and 59.7% (n = 34) were males. The actual in-hospital mortality was considerably lower than the predicted mortality risk by the German registry for acute aortic dissection type A score (16% vs 22%). The median ICU and in-hospital stay were 5 (interquartile range: 3-13) and 12 (interquartile range: 10-22) days, respectively. Postoperative complications comprised acute renal insufficiency (37%) with need for temporary (16%) or permanent dialysis (5%), delirium (26%), re-exploration for bleeding (14%), tracheostomy (14%) and new stroke (4%). A new AMDS-related complication (central stent collapse) was observed in 9% (n = 5) by postoperative computed tomography and chest X-ray. The incidence of complete central AMDS collapse did not impact 30-day mortality. CONCLUSIONS: The AMDS may be successfully used in AADA with acceptable 30-day mortality in accordance with the German registry for acute aortic dissection type A score. However, careful preoperative evaluation of the patient's individual aortic anatomy regarding potential contraindications and proper device implantation are strongly recommended to avoid complete central AMDS collapse.

Hybrid tracer - A modified novel extra oral tracer.

Introduction: Gothic arch Tracing has been a common modality in the recording of centric jaw relation. There has been two ways of recording the gothic tracing. They are extra oral and intra oral tracing. Among the extra oral tracers hight tracers are the most used tracers. Aim: Intra-oral and extra-oral tracers have a number of individual advantages and limitations. With the idea to overcome the short comings of both the tracers, hybrid tracers were made. Hybrid tracers could be a good alternative to the Hight-tracer in recording centric relation and can provide better clinical and teaching experience to the students. Methodology: The hybrid tracer is a two-component assembly, upper and lower component. The upper component has a central bearing plate and stylus in continuation with the central bearing plate. The lower component has central bearing device with three central bearing points one anteriorly and two posteriorly, and it has a tracing platform (15 × 35 mm) in continuation with the central bearing device. The length of these upper and lower components ismade to confine within the incisal rod of semi adjustable articulator. Result: hybrid tracers showed more accuracy while recording the centric jaw relation. There was more stability and equalization of pressure during the movement due to a tripod effect of three screws. Hence it provided more precise recording and being less technique sensitive. It was also more comfortable and acceptable by the patient. Conclusion: hybrid tracers hence will provide more accuracy and precision in recording of horizontal jaw relation. This will in turn help in fabricating a successful prosthesis and enhance the well-being of the patient. This tracer will also be significant in institutions for educational purpose. Clinical implication: Hybrid tracers are simple, non-technique sensitive, provide balance, equalization of pressure, stabilize the occlusal rims well, are close to the centre of rotation providing precise record and provide easy access and visibility to the operator which will help the operator in guiding the patient well for a correct jaw relation.

Is the Gothic Arch a reliable radiographic landmark for migration percentage in children with cerebral palsy?

INTRODUCTION: Reimers migration percentage (MP) is the gold standard for measuring hip displacement in children with cerebral palsy (CP). Hip surveillance registries proposed using the top of the Gothic arch (GA) as a modification in patients with acetabular dysplasia because the classical method (CM) described by Reimers may underestimate hip migration. The aim of this study is to assess the inter- and intra-observer reliability of the modified method (MM) versus the CM and identify their effect on the MP. METHODS: We performed a retrospective review of 50 children with CP, who had a hip radiograph at our institution between 1st April 2014 and 28th February 2018. All hip radiographs were carefully selected to show the presence of a GA. Four observers measured the MP using the CM and MM for each patient. Interclass coefficient was used to estimate inter- and intra-observer reliability. RESULTS: Inter-observer reliability was excellent for the CM with ICC 0.96 (95% CI 0.94 to 0.97) and good for the MM, ICC 0.78 (95% CI 0.51 to 0.89) p < 0.001. Intra-observer reliability was excellent for both methods raging from ICC 0.94 to 0.99 for the CM and ICC 0.89 to 0.95 for the MM. The mean MP was 19% for the CM and 28% for the MM (p < 0.001). CONCLUSION: The CM is more reliable than the MM to measure hip migration in children with CP. If the CM is used and acetabular dysplasia with a GA are present on the hip radiograph, then a 9% hip migration underestimation should be considered on decisions for both referral and surgical management. LEVEL OF EVIDENCE: II.

Arch reconstruction with autologous pulmonary artery patch in interrupted aortic arch.

Various surgical techniques have been developed for the repair of an interrupted aortic arch. However, tension and Gothic arch formation at the anastomotic site have remained major problems for these techniques: Excessive tension causes arch stenosis and left main bronchus compression, and Gothic arch configuration is related to cardiovascular complications. To resolve these problems, we adopted a modified surgical technique of distal aortic arch augmentation using an autologous main pulmonary artery patch. The descending aorta was then anastomosed to the augmented aortic arch in an end-to-side manner. Here, we report two cases of interrupted aortic arch that were repaired using this technique.

Evaluación de dos técnicas para el registro de relación céntrica mandibular: arco gótico versus céntrica de poder / Assessment of two techniques for the recording of mandibular central relationship: gothic arch versus power centric relation

La búsqueda de la verdadera posición mandibular con respecto a la cavidad glenoidea y la relación de los otros componentes que constituyen la articulación temporomandibular conocida como relación céntrica (RC) son esenciales para el diagnóstico, tratamiento y estabilidad del mismo. El propósito del estudio fue evaluar dos técnicas para el registro de RC (técnica céntrica de poder y técnica del arco gótico) con objeto de determinar el método más eficaz para brindar mayor veracidad en el registro, dado que, en nuestra institución, se han experimentado algunas inconsistencias durante la obtención de registros en pacientes con malformaciones o discrepancias esqueléticas considerables. Se evaluaron quince pacientes sistémicamente sanos, clase ósea II, de entre 13 y 17 años de edad, ocho del sexo femenino (53.4%) y siete del sexo masculino (46.6%). Se realizaron treinta montajes en un articulador semiajustable utilizando ambas técnicas, se monitorearon los cambios a nivel condilar utilizando el indicador de posición axial condilar (IPAC). Los resultados mostraron que no hubo diferencias significativas; sin embargo, los cambios sagitales, verticales y transversales fueron mayores con la técnica del arco gótico.

The search for the true mandibular position with respect to the glenoid fossa and the relationship of the other components which constitute the temporomandibular joint known as centric relation (CR) are essential factors for its diagnosis, treatment and stability. The aim of the present study was to assess two techniques used for recording CR: power centric technique and gothic arch technique, with the purpose of determining the most effective method to confer greater accuracy to the recording. This was triggered by the fact that in our institution some inconsistencies had been detected when taking records of patients afflicted with considerable skeletal discrepancies or malformations. Fifteen healthy skeletal class II patients were assessed. Patients' ages ranged from 13 to 17 years. Eight patients were female (53.4%) and seven male (46.6%). Using both techniques, thirty mountings were performed in a semi-adjustable articulator, condylar changes were monitored using axial condylar position indicator (API). Results revealed no significant differences, nevertheless, observed transversal, vertical and saggital changes were greater with the gothic arch technique.