Abstract: The centric relation is a mandibular position that determines a balance relation among the temporomandibular joints, the chew muscles and the occlusion. This position makes possible to the dentist to plan and to execute oral rehabilitation respecting the physiological principles of the stomatognathic system. The aim of this study was to investigate the reproducibility of centric relation records obtained using two techniques: Dawson's Bilateral Manipulation and Gysi's Gothic Arch Tracing. Twenty volunteers (14 females and 6 males) with no dental loss, presenting occlusal contacts according to those described in Angle's I classification and without signs and symptoms of temporomandibular disorders were selected. All volunteers were submitted five times with a 1-week interval, always in the same schedule, to the Dawson's Bilateral Manipulation and to the Gysi's Gothic Arch Tracing with aid of an intraoral apparatus. The average standard error of each technique was calculated (Bilateral Manipulation 0.94 and Gothic Arch Tracing 0.27). Shapiro-Wilk test was applied and the results allowed application of Student's t-test (sampling error of 5%). The techniques showed different degrees of variability. The Gysi's Gothic Arch Tracing was found to be more accurate than the Bilateral Manipulation in reproducing the centric relation records.

Abstract: A simplified technique for recording maxillomandibular relations in complete dentures is described. This technique enables the practitioner to construct a mandibular occlusal mini-rim directly in the mouth, to adjust it to the required vertical dimension and to record the maxillomandibular relations during a single appointment. The mandibular record is formed with wax, used to hold the occlusal vertical dimension anteriorly, and impression plaster, to record the centric relation posteriorly.

Abstract: Centric relation prematurities of frontal teeth are frequently found with patients who have severe orthodontic anomalies or received extensive restorative treatment. They can cause a range of symptoms ranging from loosening of the teeth to temporomandibular disorders (TMD). The objective of this work has been to derive a mathematical description of the mandibular and periodontal forces generated by anterior prematurities for different incisor relations. In order to quantify the effect of contact area (location and inclination) and the tooth inclination, a two-dimensional mathematical approach was used. Vectorisation of the forces and bending moments makes it possible to predict under which conditions the load increase mainly affecting the anterior teeth can and may cause localized pain and eventually loosening and flaring/crowding of the upper/lower incisors and under which conditions the temporomandibular joint will suffer a large increase in retrusive force, which potentially leads to TMD. For 10 patients with anterior prematurities, analysis of the incisor relation was carried out. For all cases the conclusions drawn from the mathematical model were in full agreement with the reported symptoms, which could be successfully treated.

Abstract: The purpose of this study was to address the therapeutic goals regarding the static and functional occlusion in the completion of orthodontic treatment. For such purpose, a study population comprising 20 female treated Class II malocclusion subjects with an initial mean age of 11 years underwent a two-phase treatment (orthopedics and orthodontics). The patients were diagnosed in centric relation and were treated according to the six keys for normal occlusion and functional occlusal parameters (centric relation, vertical dimension, lateral and anterior guidances, occlusal contacts and direction of forces applied on the teeth). After removal of fixed mechanics, retainers were installed and maintained for two years. Five years after orthodontic completion, the occlusal stability of the patients was evaluated regarding molar relationship and overjet, measured in dental casts. All subjects maintained the normal molar relationship and correct overjet achieved at the end of treatment, indicating a fair level of occlusal stability. The importance of the criteria of the ideal functional occlusion to ensure a better stability after completion orthodontic treatment will be discussed in detail in this paper. In addition, some clinical situations in which localized adjustments are indicated for occlusal refinement will be described.