Comparison of Techniques for Obtaining Centric Relation Based on the Reproducibility of the Condylar Positions in Centric Relation—A Systematic Review

The objective of this systematic review was to compare centric relation (CR) techniques that belong to the same method of obtaining CR (guided, graphical, or physiological method), to verify which CR technique within each method of obtaining CR generates the greatest reproducibility of the condylar positions (or mandibular position) in CR. The PubMed, Cochrane Library, SciELO, Scopus, and Web of Science databases were searched for articles published up to May 5, 2021. The search terms were combinations of “dental centric relation” (MeSH), with each of the following terms (individually): “reproducibility of findings” (MeSH); “jaw relation record” (MeSH); “chin point”; “gothic arch”; “bimanual manipulation”; “swallowing” (MeSH); and “jig.” Inclusion criteria: clinical studies in English; individuals without temporomandibular dysfunction and with complete or almost complete dentition or complete edentulous; and comparison between CR techniques belonging to the same method of obtaining CR based on the reproducibility of condylar positions in CR. For each method of obtaining the CR, the following CR techniques were considered: guided method (chin point guidance and bimanual manipulation); graphic method (intraoral and extraoral gothic arch tracing); and physiologic method (swallowing and tongue retrusion along the palate). A total of 1692 articles were screened. After the inclusion and exclusion criteria were applied, six articles were included in this review. None of the included studies evaluated edentulous individuals. All included articles compared CR techniques of the guided method. Three articles concluded that the bimanual technique showed greater reproducibility of the condylar positions in CR than the chin point guidance technique, two articles showed equivalence between these techniques, and 1 article concluded that the chin point guidance technique showed greater reproducibility of the condylar positions in CR than the bimanual technique. Thus, in this systematic review, the bimanual technique was often superior (generated greater reproducibility of the CR) or at least equivalent to the chin point guidance technique. Therefore, for individuals with complete dentition and without temporomandibular disorders, the bimanual technique is more recommended.

METHODS OF DEPROGRAMMING THE MASTICATORY MUSCLES: LITERATURE REVIEW

Deprogramming of masticatory group muscles is an integral step in determining and fixing the centric jaw relation in the diagnosis and treatment of patients with orthopedic and orthodontic pathology of the maxillary system. The review presents the main methods for determining the centric jaw ratio using deprogramming of masticatory muscles, as well as indications for the use of these methods. In complete adentia, the most acceptable are the method of non-forced control of the mandibular movements, the Dawson method, the Schiler method, the method of recording the Gothic angle, transcutaneous electroneurostimulation. The above-listed methods can be used in partial adentia as well, and in the presence of all teeth in the oral cavity. In the pathology of the temporomandibular joint, deprogramming methods using the Lucia jig, a leaf gauge, Sliding Guide, as well as the method of recording the Gothic angle will also perform a diagnostic function. With the help of these methods, it is possible to change the design of long-wearing deprogrammers and medical devices. The most universal of these methods are the method of electronic recording of the Gothic arch and transcutaneous electroneurostimulation.

Recording the Centric Relation in an Edentulous Patient Using the Existing Complete Denture Mounted with Gothic Arch Tracer

An 80-year-old man sought treatment at our hospital. He was dissatisfied with his old complete denture due to its poor stability and retention. The old complete denture had been used for about 20 years. The prolonged use of an unsuitable complete denture led the patient to be accustomed to unilateral mastication (UM). Due to the patient long-term habitual mandibular deviation, using the physiological technique to get the centric relation (CR) achieved an incorrect horizontal maxillomandibular record. This clinical report presents a technique using the existing complete denture mounted with a Gothic arch tracer to determine the CR. This technique is an inexpensive, simple, and reliable method that allows fabricating the final impression and obtaining the maxillomandibular relationship record (MMRR) in one step.

Defining the Gothic Arch Angle (GAA) as a radiographic diagnostic tool for instability in hip dysplasia

In recent years, there has been a controversial discussion about whether borderline dysplastic hips should be treated with an arthroscopic procedure or rather with an acetabular reorientation. New research suggests that a classification into stable and unstable hips may be helpful. The aim of the study was to validate (1) the intra- and interobserver reliability of a newly defined radiographic parameter named the Gothic Arch Angle, (2) the association between the GAA and previously existing measurements used to define severity of acetabular dysplasia, and (3) the correlation between radiographic measurements of acetabular dysplasia with MRI findings previously suggestive of hip instability. We defined and validated the GAA in 10 standardized radiographs of asymptomatic hips by two observers and calculated intra- and interobserver coefficients at two individual dates. Subsequently, a consecutive series of 100 patients with dysplastic hips (LCEA < 25°, Toennis grade ≤ 1) were evaluated for signs of instability on anteroposterior (a.p.) pelvic radiographs and direct MR arthrography and were divided in two groups: stable and unstable. In these patients the LCEA, the AI, the FEAR index and the GAA were radiographically evaluated. Correlation analyses and a logistic regression analysis was performed to identify the predictive value of instability for each radiographic parameter. Cutoff probabilities analysis was performed using standard receiver operating characteristic (ROC) curves to rate the predictive efficiency value of the GAA. The GAA showed excellent inter- and intraobserver reliability. A correlation was found between GAA and FEAR index. A logistic regression analysis showed that LCEA, FEAR index and GAA are distinct predictors of instability in hip dysplasia. The GAA showed the largest area under the curve (AUC 0.96), indicating it to be the best predictor of instability with an optimal cutoff value of 90° (sensitivity, 0.95; specificity, 0.93). The GAA is a new available indicator for instability and is thus suggested to be used as a future radiographic parameter for the stability of dysplastic hips. Further studies are needed to understand how this parameter might additionally predict clinical outcome in the treatment of hip dysplasia.Level of evidence: Level III, diagnostic study.

Gothic-Arch Calcite from Speleothems of the Bohemian Karst (Czech Republic): Its Occurrence, Microscopic Ultrastructure and Possible Mechanism of Growth

Gothic arch calcite, a specific crystallographic variety of calcite known from some hot springs and tufa streams, has been newly recognized in the Koněprusy Caves. The gothic-arch calcite occurs on the exteriors of exotic coralloid speleothems where it coexists with scalenohedral (dogtooth) spar crystals. The crystals exhibit microscopic ultrastructural features including deeply eroded topography, etch pits, and spiky and ribbon calcite crystallites, pointing to its extensive natural etching. Many gothic-arch calcites originated as late-stage, secondary overgrowths on older, etched dogtooth calcite crystals. Its characteristic outward curvature resulted from the recrystallization of etching-liberated fine carbonate grains and newly formed needle-fiber calcite laths, which were accumulated and bound on the faces and at the bases of corroded crystals. These intimately coexisting destructive and constructive processes of carbonate crystal corrosion and growth were probably mediated by bacteria, fungi, or other microorganisms. Fluid inclusions embedded in calcite crystals point to a vadose setting and temperatures below ~50 °C. This, combined with the wider geological context, indicates that the gothic arch calcite crystals originated only during the late Pleistocene to Holocene epochs, when the cave, initially eroded by hypogene fluids in the deeper subsurface, was uplifted to the subaerial setting and exposed to the meteoric waters seeping from the topographic surface. The radiocarbon analysis shows that gothic-arch calcite crystals are generally older than ~55,000 years, but the surface layers of some crystals still reveal a weak 14C activity, suggesting that microbiologically mediated alterations of the speleothems may have been occurring locally until now.

Axiograph and the Panoramic Radiographic Imaging Technique, an Alternative to Conventional Technique to Record Condylar Guidance

Introduction: The documentation of the maxillomandibular relationship and the recording values of condylar guidance is the most critical, yet essential step in fabrication of complete denture prosthesis and it also helps in diagnosing, treatment planning, and fabrication of the balanced complete denture prosthesis that aids in enhancing the aesthetics, and maintenance of the stomatognathic system. Various techniques are available to record the condylar guidance; One of them being axiographic technique and panoramic radiograph followed by programming the semi adjustable articulators. Aim: The aim of the present study was to evaluate and compare the condylar guidance using the conventional technique the gothic arch tracing with that of axiographic technique and the panoramic radiographs. Materials and Methods: The observational study with the clinical set up was carried out over a period between October 2018- March 2019. Twenty completely edentulous patients were selected for the study. The comparative evaluation of axiographic tracing technique, panoramic radiographic technique and the extraoral gothic arch tracing technique was conducted. The horizontal condylar guidance values obtained with these techniques were assessed. The data obtained was statistically analysed using Karl Pearson correlation test to determine the correlation between the values obtained from all the three techniques on the right side and the left side of the subjects. Paired t-test and Bonferroni Post-Hoc test were used to compare the extraoral gothic arch tracing values and Orthopantomogram values and axiographic tracing values on right side and left side of the subjects. Results: A statistically significant correlation was observed between the extraoral Gothic arch tracing technique and the panoramic radiographic technique on right (r=0.047, p-value 0.04) and left sides (r=0.55, p-value 0.01) of the subjects. The axiographic tracing showed lower values when compared with gothic arch tracing technique and the panoramic radiographic technique. (95%CI of difference was -0.49 lower). Significant differences were obtained on comparison between all three techniques on right (p-value<0.001) and left sides.(p-value 0.008). On pairwise comparison of right sides between Extraoral gothic arch Tracing and Axiographic tracing (p-value<0.001) and between axiographic tracing and Orthopantomographic tracing (p-value<0.001), were significant, while pairwise comparison on left side between Orthopantomogram and Axiographic tracings (p-value 0.01) was significant. Conclusion: The panoramic radiographic images can be used as an alternative method to that of conventional gothic arch tracing technique to obtain the condylar guidance values. The values obtained using axiographic tracings method was comparatively lower. Thus, the values obtained from axiographic technique should be used with caution or the values needs to be compared to gold standard techniques to further analyse the accuracy of the values that can be used as a valuable aid in setting the condylar guidance in semi-adjustable articulators.

A Comprehensive Systematic Review In Search Of Evidence for Pragmatic Altercations in Simplified Denture

Aim: To explore the evidence available to evaluate if simplified dentures could be as effective as the conventional complete dentures. Materials and Methods: A total of 1,482 articles were obtained using keywords in a Boolean search operator in the PubMed search engine, Google Scholar and Cochrane Library. Duplicates were removed and the remaining articles were subjected to a title analysis which yielded a total of 20. Further analysis of the article abstracts led to an exclusion of four articles. The remaining 16 articles were subjected to full text analysis which finally yielded a total of 11 articles. Results: The cumulative results of the meta-analysis for oral health-related quality of life, patient satisfaction and professional quality of denture show no significant difference ( P > .05) between conventional and simplified dentures. Conclusion: Based on the available evidence adjusted for the potential literature/geographic bias, we conclude that the conventional procedures in complete denture fabrication such as facebow and gothic arch tracing do not improve the quality of the denture outcome from patients’ perspective and simplified dentures are equally effective as conventional complete dentures.

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