Abstract: The purpose of this study was to investigate the effect of an anterior flat plane deprogramming appliance (Jig) in 40 subjects for whom centric relation (CR) records were obtained before and after the use of the appliance. Incisal overbite and overjet dimensions and three-dimensional instrument condylar representation using the Panadent condylar path indicator (CPI) were recorded from maximum intercuspation and centric relation. Subjects were assessed subjectively to determine the degree of difficulty manipulating the mandible to obtain the centric relation record. The mean overbite difference from maximum intercuspation (MI) to centric relation without (CR) and with (CRJ) the appliance were statistically significant and decreased 1.58 mm and 2.23 mm, respectively. The mean overjet values from MI to CR and CRJ were statistically significant and increased .44 mm and .57 mm, respectively. Significant differences were determined on the Panadent articulator for the absolute vertical (Z) and absolute horizontal (X) values for centric relation with and without the appliance. The number of subjects who exceeded the threshold values of 2 mm for CPI recordings in either the horizontal or vertical direction was 7 (18%,) from MI to CR and 16 (40%) from MI to CRJ. The Lucia-type jig deprogramming appliance provides a centric relation record with greater displacement from MI than a centric relation record alone. This appliance may be a useful adjunct in a patient where mandibular manipulation in taking a centric relation bite registration is deemed not easy.

Abstract: This study investigates the differences in condylar position between centric relation (CR) and centric occlusion (CO) in Japanese orthodontic patients before treatment. We employed 150 consecutive cases (age range: 6-57 years) for the study. Dental casts were mounted on a Panadent articulator with a power centric CR bite record. The differences in condylar position between CR and CO in all three spatial planes were measured using the Panadent Condyle Position Indicator (CPI). The subjects were divided into groups by age, gender, mandibular plane angle or angle classification. No significant differences in the magnitude of CPI measurements were found among the groups. The three-dimensional distances of condylar displacement on both sides were almost identical, and the superoinferior displacement (S-I) was greater (P < .0001) than the anteroposterior displacement (A-P). The S-I was greater (P = .02) on the left side than on the right side, while the A-P displacement was smaller (P < .0001) on the left side than that on the right side. Significant condylar displacement (2.0 mm for S-I and A-P, 0.5 mm for the lateral displacement, L) was found frequently in L (31.3%), S-I, and A-P, in that order. Fifty-eight (38.7%) of the subjects had significant displacement in L, S-I, or A-P. Moreover, Angle Class III subjects tended to have significant condylar displacement toward the left side. The results suggest that orthodontists should be aware of a high incidence of condylar displacement in Japanese orthodontic patients and measure condylar displacement before the start of comprehensive orthodontic treatment to unmask real jaw relationships and avoid possible misdiagnoses.

Abstract: This research consisted of a quantitative assessment, and aimed to measure the possible discrepancies between the maxillomandibular positions for centric relation (CR) and maximum intercuspation (MI), using computed tomography volumetric cone beam (cone beam method). The sample of the study consisted of 10 asymptomatic young adult patients divided into two types of standard occlusion: normal occlusion and Angle Class I occlusion. In order to obtain the centric relation, a JIG device and mandible manipulation were used to deprogram the habitual conditions of the jaw. The evaluations were conducted in both frontal and lateral tomographic images, showing the condyle/articular fossa relation. The images were processed in the software included in the NewTom 3G device (QR NNT software version 2.00), and 8 tomographic images were obtained per patient, four laterally and four frontally exhibiting the TMA's (in CR and MI, on both sides, right and left). By means of tools included in another software, linear and angular measurements were performed and statistically analyzed by student t test. According to the methodology and the analysis performed in asymptomatic patients, it was not possible to detect statistically significant differences between the positions of centric relation and maximum intercuspation. However, the resources of cone beam tomography are of extreme relevance to the completion of further studies that use heterogeneous groups of samples in order to compare the results.

Abstract: This study examines the validity of articulare for mandibular length measurements by exposing 3 lateral cephalograms on each of 60 consecutive patients. The radiographs were exposed with the patient in a closed-mouth position in habitual occlusion, a closed-mouth position with the patient in centric relation, and in an open-mouth position. The linear distances (mm) of articulare (Ar) to pogonion (Pog), Ar to gonion (Go), and Go to Pog were measured on the 2 closed-mouth cephalograms and compared with each other as well as the linear distances of condyle (Co) to Pog, Co to Go, and Go to Pog measured from the open-mouth cephalogram on each individual. Product-moment correlation coefficients were used to measure the linear associations among the mandibular measurements from the 3 techniques. Repeated measures analyses of variance were also fit to estimate the correlations between the 3 measurements adjusted for age and sex. The results of this study show that measurements taken from both closed-mouthed techniques agreed extremely well (intraclass correlation coefficient = 0.99). In addition, measurements from both closed-mouth techniques highly agreed with the corresponding measurements taken with the open-mouth technique (intraclass correlation coefficient = 0.94). This data suggests that measurements taken from Ar correlate very well with measurements taken from Co and that this correlation is not dependent on whether the patient is positioned in habitual occlusion or centric relation.

Abstract: This study compared the mandibular displacement from three methods of centric relation record using an anterior jig associated with (A) chin point guidance, (B) swallowing (control group) and (C) bimanual manipulation. Ten patients aged 25-39 years were selected if they met the following inclusion criteria: complete dentition (up to the second molars), Angle class I and absence of signs and symptoms of temporomandibular disorders and diagnostic casts showing stability in the maximum intercuspation (MI) position. Impressions of maxillary and mandibular arches were made with an irreversible hydrocolloid impression material. Master casts of each patient were obtained, mounted on a microscope table in MI as a reference position and 5 records of each method were made per patient. The mandibular casts were then repositioned with records interposed and new measurements were obtained. The difference between the two readings allowed measuring the displacement of the mandible in the anteroposterior and lateral axes. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no statistically significant differences (p>0.05) among the three methods for measuring lateral displacement (A=0.38 +/- 0.26, B=0.32 +/- 0.25 and C=0.32 +/- 0.23). For the anteroposterior displacement (A=2.76 +/- 1.43, B=2.46 +/- 1.48 and C=2.97 +/- 1.51), the swallowing method (B) differed significantly from the others (p 0.05) was found between chin point guidance (A) and bimanual manipulation (C). In conclusion, the swallowing method produced smaller mandibular posterior displacement than the other methods.

Abstract: There has been much discussion regarding the ideal position of the condyle in the mandibular fossa. Although the centric relation position (CR) is used as a reference, some authors do not believe that it is physiologic. Thus, the aim of this study was to evaluate in a group of asymptomatic individuals the position of the condyle in the mandibular fossa at maximum intercuspation (MI), with a occlusal splint and with a Lucia jig between the teeth. It was analyzed by means of magnetic resonance imaging (MRI), transcranial radiography imaging and analysis of horizontal axis of rotation from casts mounted on an articulator. The results showed that even if patients had mandibular displacement in positions of CR, habitual maximum intercuspation and with the occlusal splint, confirmed by means of the analysis of the horizontal axis of rotation, the images showed no statistically significant differences among condylar positions. It can therefore be concluded that the positions analyzed were similar and that transcranial radiography seems to be a reliable method for analyzing condylar position.

Abstract: Centric relation is the most difficult, yet, most important step in treating edentulous patients with complete dentures However, a review of dental literature reveals that the philosophies and methods to make the actual registration vary greatly It is generally agreed that centric relation records can be grouped into four categories- direct checkbite (interocclusal) recordings, graphic recordings (intra-oral and extra-oral), functional recordings, and cephalometrics This article discusses the pros and cons of the various methods and techniques of recording centric jaw relations However, the skill of the dentist and cooperation of the patient are probably the most important factors in securing an accurate centric relation record

Abstract: Even if the relationship between condylar position and/or temporomandibular disorders (TMDs) and dentofacial deformity is controversial in literature, several patients presenting malocclusion refer to pain and TMDs as the main trouble. There are also various opinions concerning the alterations or improvements of temporomandibular joint symptoms after orthognathic surgery. In agreement with the experience of Universitat Wurzburg, the purpose of this study was to evaluate the validity of splint technique to reproduce centric condyle positioning in bimaxillary osteotomy surgeries for the patients with skeletal-facial disorders and coexisting TMDs. The present study is based on a sample of patients with maxillomandibular malocclusion and coexisting TMDs who underwent bimaxillary osteotomy surgeries with splint technique. All patients underwent a protocol consisting of various steps: Pretreatment evaluation consisted of a questionnaire on subjective symptoms, clinical examinations, photographs of the occlusion, plaster casts, bite registrations, examination of the posture; instrumental examinations; panoramic, teleradiography, and cephalometric analysis; stratigraphy of TMD; and electromyography. Presurgical treatment consisted of therapy by modified Farrar splint associated with a pharmacologic therapy for the acute symptoms; orthodontic treatment associated with a global reeducation of the posture and a pompage of the masticatory muscles; and manufacturing of an occlusal splint in the most posterior asymptomatic position. Surgical treatment consisted of bimaxillary osteotomies performed after registering condyle position by a "repositioning" plate. The condyle position is guided by the intermaxillary fixation with the interposition of the occlusal splint. Surgery on maxillary is performed through Le Fort I osteotomy and fixation. Later, sagittal splint osteotomy of mandible is performed. Position of ramus and TMD complex is guided by the positioning of the plates modeled previously and fixed to maxillary and ramus in the same relationship registered with the splint. Finally, fixation of mandibular osteotomies is performed. Postsurgically patients underwent orthodontic treatment (to stabilize occlusal and articular changes) and physical therapy. After the end of treatment, stability of results was investigated with clinical, radiologic, and electromyographic valuations. The authors' experience suggests that, as in orthognathic surgery, identification of a correct condyle-fossa relationship (achieved by splint and repositioning plate) is essential to guide osteosynthesis after sagittal split osteotomy in patients affected by TMDs and ultimately affects the stability of the procedure.

Abstract: A method for fabrication of record bases which is used in implant dentistry has been described. This method is cost effective because it does not need extra equipment for making the maxill...

Abstract: This study was performed to evaluate the consistency of four different centric relation records and comparing their horizontal deviation with the control subgroup (recordings by intraoral tracing technique) and with each other taken from ten different edentulous individuals. The problems of occlusion extend into nearly all branches of dentistry. While the principles involved are the same, their application should be different according to the situation. Centric relation can be located by many techniques but there is some variability in the results obtained by any of them. Therefore, each dentist should have a means of comparing his registrations so that an intelligent selection can be made. The dentist should not fall into the error of trying to make the same application in all situations. An accurate centric jaw relationship record is important when constructing dentures. It is a three-dimensional record and, to be accurate for a given individual, the relationship, anteroposteriorly and laterally, should be recorded at the occlusal vertical dimension deemed correct for the individual. This study demonstrates a significant statistical difference between the recordings taken with intraoral tracing technique and among 71 other subgroups evaluated by two techniques. The recordings made with the extraoral Gothic arch tracing technique values were closer to the control as compared with two other subgroups in both the evaluations. Furthermore this study does not show the superiority of any of method for recording centric jaw relation on one another. This study only shows the deviation of the recordings made with four different techniques among different subgroups. Accurate records for centric jaw relation can be made with any of these techniques, but the chances of errors are more in tactile methods as compared to graphic methods.

Abstract: A female presented to the office with a chief complaint concerning the esthetics of the porcelain-fused-to-metal (PFM) crowns on her maxillary lateral incisors. The objective was to use contemporary materials and techniques to have them blend better with her natural dentition. The PFM crowns had been completed at different times during her life. She said they did not match each other or her adjacent natural tooth structure (Figure 1).

Abstract: Objective: To compare, in the horizontal plane, the mandibular positions determined by two methods for registering the centric relation (CR): inclination of the head backward (IHB) and unstrained hinging movement (UHM), in edentulous patients. The null hypothesis was that there is not difference between the two methods. Material and Methods: Twenty edentulous subjects were selected for this study (n=20). All patients were manipulated to CR position using the methods IHB and UHM. The CR measure of each method was registered in one extraoral device, which was fixed at the maxillary and mandibular record bases. For each patient, the two CR positions were registered in the same extraoral device. To measure the anteroposterior and lateral linear variations between the points registered for each technique, it was used a profile projector (Model 6C, Nikon/USA). The data (μm) were statistically analyzed using the Tukey test (p 0.05). Conclusion: It can be conclude that the method UHM presented a higher mandibular retrusion than the method IHB.

Abstract: Fabrication of occlusal splints in centric relation for temporomandibular disorders (TMD) patients is arguable, since this position has been defined for asymptomatic stomatognathic system Thus, maximum intercuspation might be employed in patients with occlusal stability, eliminating the need for interocclusal records This study compared occlusal splints fabricated in centric relation and maximum intercuspation in muscle pain reduction of TMD patients Twenty patients with TMD of myogenous origin and bruxism were divided into 2 groups treated with splints in maximum intercuspation (I) or centric relation (II) Clinical, electrognathographic and electromyographic examinations were performed before and 3 months after therapy Data were analyzed by the Student's t test Differences at 5% level of probability were considered statistically significant There was a remarkable reduction in pain symptomatology, without statistically significant differences (p>005) between the groups There was mandibular repositioning during therapy, as demonstrated by the change in occlusal contacts on the splints Electrognathographic examination demonstrated a significant increase in maximum left lateral movement for group I and right lateral movement for group II (p 005) in the electromyographic activities at rest after utilization of both splints In conclusion, both occlusal splints were effective for pain control and presented similar action The results suggest that maximum intercuspation may be used for fabrication of occlusal splints in patients with occlusal stability without large discrepancies between centric relation and maximum intercuspation Moreover, this technique is simpler and less expensive