ARCUS digma下颌运动轨迹记录仪获取殆架参数精确度的研究

目的以(牙合)架设定值为标准,研究采用ARCUS digma下颌运动轨迹记录仪获取(牙合)架参数误差的大小.方法将ARCUS digma记录仪的测量装置固定在(牙合)架上,测量(牙合)架模拟下颌运动的参数.调整(牙合)架前伸髁导,从-30°到60°,每次间隔15°;Bennett角分别设定为4°、10°、20°、30°;前伸切导从0°到80°,间隔10°.每次调整设定值后测量5次,分析测量值和设定值间的误差.结果前伸髁导测量值与设定值之差为-2.9°～2.4°,前伸切导的在-2.9°～2.9°,差异无显著意义(P＞0.05).Bennett角测量值均较设定值小,差值为-4.1°～-0.3°,有显著意义(P＜0.01).结论采用ARCUS digma下颌运动轨迹记录仪获取(牙合)架参数精确度高,有利于提高修复体咬合质量.     

Accuracy of recording horizontal condylar inclination and Bennett angle with the Cadiax compact

This study assessed the accuracy of an electronic hinge axis tracing device (Cadiax compact) in measuring the horizontal condylar inclination (HCI) and the Bennett angle. The hinge axis movements were simulated with an articulator to which the hinge axis tracer was attached. On the articulator the pre-set HCI values were 20 degrees, 40 degrees and 60 degrees, the pre-set Bennett angles were 0 degrees, 5 degrees, 10 degrees, 15 degrees, 20 degrees. The maximum measuring errors ranged from 0 to 3.4 degrees (in average 1.2 degrees ) and yielded statistically significant differences between articulator setting and Cadiax compact measurement (P < 0.05) except the HCI of 40 degrees and the Bennett angle of 0 degrees. Because of the small range of the maximum measuring error the Cadiax compact represented reasonable accuracy for clinical application in anterior guidance restorations.     

Effect of interocclusal records on the condylar path of the articulator

Although there are studies on materials used for interocclusal records, there are no scientific data how the condylar path is influenced by the positional interocclusal records. The purpose of this in vitro study was to determine the effects of different interocclusal mediums on condylar inclination of the articulator. The materials selected for this experiment were: two addition type silicone pastes, two silicone putty materials and two waxes. The samples of protrusive records were performed on a Quick-Master semiadjustable articulator (FAG Dentaire). The same pre-established eminentia angles were used during the experiment for each type of materials. To improve the control of the condylar angles a protractor was mounted to the upper member of the articulator at right angels to each condylar fossa housing. A stylus moving simultaneously with the condylar fossa marked the eminentia angle on the protractor. 108 interocclusal records were performed and in 24 hours they were returned to the articulator. Then the articulator was adjusted and the settings of the eminentia angle were recorded. Numerical deviations between the pre-established and the adjusted settings in degrees were subjected to statistical analysis. The results indicated that these deviations for addition type silicones were significantly smaller than that of the other materials. The two waxes proved to be the least accurate materials. It is concluded that the condylar inclination is influenced by the properties of the registration materials, which may increase the shortcomings of the protrusive bite records.     

Predicted incidence of excursive occlusal errors in common modes of articulator adjustment

PURPOSE: Functional relationships between occlusal errors and articulator settings have been the subject of numerous investigations. It is, however, not known how frequently errors of a certain size occur under practical conditions. This study attempted to estimate the frequency of occlusal errors that can be expected with the different levels of registration and articulator adjustment that are currently used. MATERIALS AND METHODS: In 57 asymptomatic subjects, individual articulation parameters, including the condylar and Bennett angles, the spatial relation of dental arches, and the intercondylar distance, were determined experimentally. Tooth-guided lateral movements of the subjects' casts were simulated in a virtual articulator that was programmed to the individual parameters of each person. With respect to this reference setting, occlusal errors that would emerge with different modes of semi-individual adjustment were calculated. The intercondylar distance thereby remained fixed at 110 mm. RESULTS: With complete mean value setting, occlusal errors would exceed 200 microns at the second molar in 16% of the subjects and 300 microns in 6% of the subjects. Individual facebow registration of condylar angles and spatial relations would reduce these rates to 13% (200 microns) and 3% (300 microns). With additional setting of Bennett angles, occlusal errors would exceed the mentioned limits in no more than 1.6% and 0.1% of cases, respectively. This extensive mode of adjustment became, however, increasingly ineffective with higher demands for occlusal accuracy. CONCLUSION: Complete mean value setting is associated with a relatively low risk of occlusal errors exceeding tolerance limits that are widely accepted in practice. Compared to mean value setting, facebow registration of condylar angle and relations yields no profitable improvement of occlusal accuracy.     

解析法分析(牙合)架参数测量误差导致的前伸(牙合)误差

目的:理论计算ARCUSdigma系统测量架参数误差所导致的牙合架前伸牙合误差。方法:通过推导数学公式,建立解析法分析下颌第一磨牙区域前伸误差的方法。并计算ARCUSdigma系统对各前伸髁导斜度、切导斜度设定值的最大、最小和平均测量值所导致的前伸牙合误差。结果:前伸髁导斜度小于30°时,最大、最小和平均测量值导致的咬合误差均小于0.2mm;而切导斜度的最大、最小测量值导致的咬合误差稍大。当切导斜度为80°、前伸髁导斜度达到45°时,测量平均值也会导致较大的前伸误差。结论:采用ARCUSdigma系统获取牙合架参数误差所导致的前伸误差较小。如前伸髁导斜度小于30°,不需多次测量;而前伸切导斜度应取多次测量结果的平均值。对于大于30°前伸髁导斜度、大于70°切导斜度的测量值的采用,则要慎重。     

Reproducibility of jaw movements in patients with craniomandibular disorders

It has never been investigated, if mandibular movements of patients with craniomandibular disorders (CMD) result in a lower reproducibility of dynamic functional parameters which are used for the individual articulator setting. The aim of the present study was to compare the reproducibility of electronically registered functional parameters in patients with CMD and in a control group. Dynamic functional parameters were recorded in 30 patients and 30 volunteers with a computerized ultrasound system (ARCUSdigma). The whole registration was performed three times during one session and three times at a second session 1 week later. The horizontal condylar inclination in the patient group gave a standard deviation of 2.17 degrees +/- 0.95 degrees , indicating poorer reproducibility than in the volunteer group, for which the standard deviation was 1.37 degrees +/- 0.42 degrees . The reproducibility of measurements of the Bennett angle was also poorer in the patient group than in the volunteer group, with standard deviations of 1.70 degrees +/- 0.62 degrees and 1.22 degrees +/- 0.40 degrees , respectively. The standard deviations calculated for determination of incisal inclination during laterotrusion was 3.02 degrees +/- 1.49 degrees for patients and 2.30 degrees +/- 1.17 degrees for volunteers. The standard deviations for incisal inclination during protrusion was 2.02 degrees +/- 0.95 degrees for patients and 2.06 degrees +/- 1.82 degrees for volunteers. The reproducibility of measurement of horizontal condylar inclination, Bennett angle and incisal inclination during laterotrusion therefore showed significantly lower reproducibility in the patient group than in the volunteer group (P < 0.05). The overall reproducibility of the measurements was nevertheless good in both groups, with standard deviations under 3.1 degrees , so that an individual setting of an articulator seems useful even in patients with CMD.     

A comparison of protrusive interocclusal records to pantographic tracings

The rationale for recording protrusive mandibular movement is to accurately adjust an articulator. Techniques to record condylar inclination include radiographic interpretation, extraoral tracings, and intraoral recording materials. This study compared the protrusive settings on an articular adjusted by a pantograph to protrusive settings recorded by two intraoral recording materials, one a polyvinyl siloxane material and one a laminated, metalized wax. Pantographs were completed for 20 patients by using a kinematic hinge axis and conventional pantographic techniques. The patients also had three protrusive interocclusal records made with two intraoral registration materials completed and averaged. The average condylar inclination recorded with a pantograph (29.5 degrees) was greater than the recording by either intraoral registration material. Standard deviations ranged from 4.1 degrees to 6.6 degrees. An analysis of variance showed that the condylar inclination recorded by wax was statistically less than recorded with a pantograph. A comparison between the pantograph and the polyvinyl siloxane displayed no statistically significant difference in recording condylar inclination.     

Sagittal condylar guidance as determined by protrusion records and wear facets of teeth.

The maxillary and mandibular casts of 45 healthy and dentulous subjects, with conspicuous wear facets on canines and molars, were mounted on a semiadjustable articulator. The sagittal condylar guidance was determined by two methods: (1) using a protrusion wax interocclusal record and (2) by matching the wear facets of opposing canines and contralateral molars. There was a substantial bilateral symmetry of the right and left sagittal condylar guidance angles using both methods. There were, however, significant differences between the mean angles of the two methods, about 31 degrees (protrusion record) versus about 24 degrees (wear facets). This, in association with rather low coefficients of linear determination, suggested that the two methods of recording the sagittal condylar guidance angle were based on totally different phenomena.     

A new articulator emphasizing centric occlusion and the anterior determinants.

A new articulator is described which has the advantages of the rigidity of a simple articulator in the upper member and the flexibility of an adjustable articulator in the lower member. A link between the members and the frame along with the posterior controls establishes a full range of functional chewing movements and defines the extreme lateral or border paths. The articulator has condylar element controls which permit releasing and remounting the mandibular cast in a manner that serves the same function as the split-cast technique, but this method is faster and shows the amount of discrepancy. The condylar element control is an improvement over existing devices for comparing interocclusal records in that it not only indicates differences in position but it also provides quick remounting of the casts in a working articulator. Other features of the articulator are: (1) a condylar lock mechanism which is activated by only a half turn, (2) adjustable spring tension, (3) precise long centric and wide centric controls, (4) an incisal pain which can be removed and replaced on the articulator without changing its setting, (5) a Bennett movement carefully selected to avoid the complication of a pantograph type of face-bow, and (6) a new sponge wall type of mounting plate which supports both casts for simultaneous mounting.     

Comparison of condylar guidance setting obtained from a wax record versus an extraoral tracing: a pilot study

STATEMENT OF PROBLEM: Protrusive condylar angles can be determined by use of wax protrusive records (WPR), pantographic tracings (PT), and occlusal wear facets. These methods generate different angles in the same patient. PURPOSE: The purpose of this study was to compare the condylar inclination angles found by use of the WPR in a Hanau articulator with those found by use of the Whip-Mix PT quick-set recorder. The occlusal wear facet method was not part of this study. MATERIAL AND METHODS: Ten subjects were chosen at random from a dental school patient population. All subjects had a majority of maxillary and mandibular teeth present and according to the examination criteria used in the school's Division of Occlusion, they were healthy with no signs/symptoms of temporomandibular disorders. The WPR was accepted when it was evident that the patient had protruded straight forward at least 6 mm anterior to centric relation, as shown on the Hanau articulator by the condylar spheres having moved anteriorly an equal distance of 6 mm on both sides. The condylar inclination on the articulator was adjusted accordingly. The PT was used according to the manufacturer's directions, which included the use of an intraoral clutch adapted to the mandibular arch, connected to an extraoral facebow with bilateral inscribing pointers. A holder frame was adapted to the face with bilateral flags where the inscribing pointers traced the protrusive movement of the jaw. All the readings were in degrees. No control was used in this project. To test whether there was a significant difference between the 2 independent samples, a Mann-Whitney U test was performed (P=.01). RESULTS: The mean results for the WPR were as follow: right side (28.1 degrees, SD 8.94); left side (31.50 degrees, SD 9.73). For the PT, results were: right side (41.10 degrees, SD 7.53); left side (35.5 degrees, SD 6.43). When right and left side protrusive condylar angles were combined, the values were: WPR (29.80 degrees, SD 9.25); PT (38.30 degrees, SD 6.98). The differences on the right condylar values were significant (P=.01). There was no statistical difference on the left side. CONCLUSIONS: Within the limitations of this study, it was concluded that the PT technique yielded greater values for the protrusive condylar inclination than the WPR.     

An in vitro evaluation of the reliability and validity of an electronic pantograph by testing with five different articulators

STATEMENT OF PROBLEM: The degree of reliability and validity of a new electronic pantographic instrument, the Cadiax Compact, has not been established. PURPOSE: The purpose of this study was to test the reliability and validity of the electronic pantograph in calculating condylar settings for 5 different articulators (Denar D5A, Denar Mark II, Whip Mix 8500, Hanau Modular, and Panadent PCH). MATERIAL AND METHODS: Pantograph sensors were mounted to each articulator with custom-made mounting devices. Border movements were made on each articulator with known condylar settings to produce readings at 3-, 5-, and 10-mm condylotrack distances. The condylar settings investigated included horizontal condylar inclination (HCI), immediate mandibular lateral translation (IMLT), progressive mandibular lateral translation (PMLT), top wall, and rear wall. Reliability was assessed by the relative size of standard deviations. Validity was tested with 1-way analysis of variance and the Tukey HSD Test (alpha=.05). RESULTS: The reliability readings for the condylar settings at the 10-mm condylotrack distance, for the most part, were more consistent than those at the 5-mm distance, which, in turn, were more consistent than those at the 3-mm distance. When there were exceptions to this trend, the differences in standard deviations were very small (0.006 mm for IMLT, 0.03 and 0.12 degrees for HCI). When comparing validity between the condylotrack distances, the smallest deviations, in general, were found at the 10-mm distance, the next smallest at the 5-mm distance, and the largest, at the 3-mm distance for HCI. For PMLT, in general, the 10-mm and 5-mm deviations were smaller than the 3-mm deviation. For IMLT, there was no significant difference between the 3-, 5-, and 10-mm deviations. In analyzing validity between the articulators, the smallest deviations from the preset values, in general, were found with the Denar Mark II. CONCLUSION: The standard deviations for assessing reliability and the mean deviations for assessing validity were both relatively small in comparison to the average values of the condylar determinants. Therefore, the electronic pantograph was determined to be both reliable and valid.     

A Comparative Evaluation of Condylar Guidance Value from Radiograph with Interocclusal Records made During Jaw Relation and Try-in: A Pilot Study

The purpose of this study was to evaluate the reliability of programming the articulator using the radiographs and the interocclusal records made during Jaw relation (Arrow point tracing) and Try-in stage. The study comprised of 15 edentulous subjects with well formed maxillary and mandibular ridges, with no signs and symptoms of temporomandibular joint disorders and neuromuscular disorders. Digital Orthopantomograph was taken for all the subjects. The condylar guidance angles were traced on Orthopantomograph for right and left sides and the values were recorded. The protrusive interocclusal records were made at jaw relation stage and at try-in stage using bite registration paste (Bitrex- vinyl polysiloxane) for all subjects. These interocclusal records were used to programme the Semi-adjustable articulator (Hanau Wide Vue) and the condylar guidance values on the right and left sides were recorded. The condylar guidance values so obtained were compared with the values obtained by Orthopantomograph. The condylar guidance values obtained by the various procedures were subjected to statistical analysis. The results showed statistically significant difference between the condylar guidance values obtained from Orthopantomograph (Radiograph) and the condylar guidance values obtained at the stage of jaw relation and also between Orthopantomograph and condylar guidance values obtained at the stage of Try-in. Condylar guidance values obtained from the Radiographs were higher than those obtained at the stage of Jaw relation and at the stage of Try-in. However, we notice that the mean condylar guidance values obtained at the stage of Try-in were nearer to the mean condylar guidance values obtained on the Radiographs.     

A new semiadjustable articulator. Part III. An investigation of the capability of the Hanau XP-51 articulator.

A new semiadjustable articulator, the Hanau XP-51, was investigated by comparing its movements at the cusp level to those of a Stuart articulator when guided by straight condylar elements. No clinical trial was undertaken in this investigation, and no mandibular movements were registered on the Stuart articulator for transfer to the Hanau XP-51 articulator. A method of comparison and mathematical formulae were described whereby specific angles were calculated for both articulators. All tabulated angles were correlated by determining the least-squares slope of the observed angular variation as a function of the three independent variables in a computerized program. The standard deviation from these was calculated for each articulator, and the differences were found to be very small. It was concluded that the experimental Hanau XP-51 articulator could reproduce specific movements made by the Stuart articulator. Further, the adjustable posterior wall within the condylar housing was found to compensate for the lack of an adjustable intercondylar distance on this articulator.     

Reproducibility of lateral excursive tooth contact in a semi-adjustable articulator depending on the type of lateral guidance

The purposes of this study were (i) to compare the reproducibility of lateral tooth contacts of casts mounted in a semi-adjustable articulator when condylar guidance was set by different methods and (ii) to assess the margin of error of the variations of condylar guidance without changing lateral tooth contacts, depending on the type of lateral guidance. In subjects with different types of lateral guidance, intraoral lateral tooth contacts identified with occlusal registration strips were compared with those identified by use of a semi-adjustable articulator, setting the condylar guidance in four different ways: using protrusive wax wafers, by axiography and by adding and subtracting 5 degrees from the value of condylar guidance obtained by protrusive wax wafers. Tolerance to variations of condylar guidance without changing lateral tooth contacts was determined by increasing and decreasing the value of condylar guidance until lateral tooth contacts changed. Different ways of setting condylar guidance on a semi-adjustable articulator give rise to different values of condylar guidance in the same subject. The occlusal repercussions of these variations of condylar guidance values depend on the type of lateral guidance. Canine protection had the greatest tolerance to variations in the setting of condylar guidance without changing lateral occlusal contacts.     

Evaluation of an improved orthognathic articulator system: 1. Accuracy of cast orientation

A systematic study was carried out using plastic model skulls to quantify the accuracy of the transfer of face bow registration to the articulator. A standard Dentatus semi-adjustable articulator system was compared to a purpose built orthognathic articulator system by measuring the maxillary occlusal plane angles of plastic model skulls and of dental casts mounted on the two different types of articulators. There was a statistically significant difference between the two systems; the orthognathic system showed small random errors, but the standard system showed systematic errors of up to 28°.     

Estimated and true hinge axis: a comparison of condylar displacements.

The purposes of the investigation were: i) to compare the condylar displacements from centric slides for 74 sets of casts mounted with an estimated versus a true hinge axis; ii) to determine the error in hinge axes location on the recording of condylar displacements from centric slides; and iii) to define the reproducibility of the Mandibular Position Indicator (MPI), a method of measuring condylar (in vitro) displacements from centric relation position. The findings revealed that routine use of the true hinge axis to obtain MPI readings for analysis of diagnostic casts is not warranted. The mean standard error of MPI double readings attributed to both hinge axes location was 0.4 mm for each component in the sagittal plane. Of the 0.4 mm of mean standard error, 0.2 mm was contributed by the lack of reproducibility of the MPI. The centric relation bite registration technique outlined in this study always captured a superior articulator position of the condylar mechanism. The condylar distractions and deflections from centric relation to maximum intercuspation were primarily in an inferior direction with a smaller posterior component.     

Age Changes in Horizontal Condylar Angle: A Clinical and Cephalometric Study

Determination of condylar inclination is important when restoring the occlusal surfaces of teeth. It is important to know the changing trends in horizontal condylar inclination with age so as to have an idea about the cuspal morphology. Aims and objectives: a) to determine the effect of age changes in horizontal condylar inclination using articulator method and radiographic method (cephalometry) b) to compare the values of horizontal condylar inclination obtained using articulator method with that of cephalometric method c) to ascertain the symmetry of horizontal condylar angle on both right and left side on an articulator. 40 dentulous individuals with Angle’s class I occlusion were selected for the study. They were divided into four groups Group I: 20–29 years, Group II: 30–39 years, Group III: 40–49 years, Group IV: 50–59 years. Horizontal condylar inclination was determined on right and left side for each individual using protrusive interocclusal record in a Dentatus (ARL) semiadjustable articulator. Cephalometric recording was carried out twice on the left side, once in centric occlusion position and then in protrusive position. The two radiographs were superimposed to draw a line connecting the shifting position of condylion on an acetate tracing paper. This line when joined with Frankfurt horizontal plane gives the horizontal condylar inclination. Analysis of variance (ANOVA) revealed that there was a significant difference in horizontal condylar angle values in all the four groups which were statistically significant. There is a decrease in horizontal condylar angle values from Group I to Group IV. Horizontal condylar values obtained by articulator method and cephalometric method showed no significant difference for all the four groups tested. When horizontal condylar values obtained on right and left sides of Dentatus articulator were compared there was not much of a significant difference. Horizontal condylar values showed a decreasing trend with increasing age, i.e, as age advances there is a flattening of condylar head. Both articulator and cephalometric method yielded no significantly different values and hence both the methods can be used for determining condylar inclination. The difference in values of horizontal condylar angle on right and left sides were insignificant.     

安氏Ⅰ类和Ⅱ类1分类错患者下颌位置的研究

目的：研究错He患者下颌处于正中关系位（centric relation,CR)和最大牙尖交错位（maximum intercuspation,MI)时髁突位置与咬合关系的变化。方法：使用PanadentHe架系统和髁突位置测量仪,检查50名错He患者（安氏Ⅰ类、Ⅱ^1类各25人）的下颌位置和咬合情况。结果：几乎所有的患者均存在CR－MI髁突位置差异,在矢状方向上多为向上移位,65％的受检者CR初始接触位于单侧最后磨砑,当下颌从CR位移至MI位时,咬合变化主要表现为磨牙关系近中化、切牙覆He加深覆盖变浅。安氏Ⅰ类与Ⅱ^1类错He之间,上述改变的差异无显著性。结论：正畸治疗前必须了解患者下颌处于正中关系时的咬合情况,发现He与下颌位置之间的不协调。     

Condylar guidance: correlation between protrusive interocclusal record and panoramic radiographic image: a pilot study

Purpose: The purpose of this study was to compare the sagittal condylar angles set in the Hanau articulator by use of a method of obtaining an intraoral protrusive record to those angles found using a panoramic radiographic image. Materials and Methods: Ten patients, free of signs and symptoms of temporomandibular disorder and with intact dentition were selected. The dental stone casts of the subjects were mounted on a Hanau articulator with a springbow and poly(vinyl siloxane) interocclusal records. For all patients, the protrusive records were obtained when the mandible moved forward by approximately 6 mm. All procedures for recording, mounting, and setting were done in the same session. The condylar guidance angles obtained were tabulated. A panoramic radiographic image of each patient was made with the Frankfurt horizontal plane parallel to the floor of the mouth. Tracings of the radiographic images were made. The horizontal reference line was marked by joining the orbitale and porion. The most superior and most inferior points of the curvatures were identified. These two lines were connected by a straight line representing the mean curvature line. Angles made by the intersection of the mean curvature line and the horizontal reference line were measured. The results were subjected to statistical analysis with a significance level of p < 0.05. Results: The radiographic values were on average 4° greater than the values obtained by protrusive interocclusal record method. The mean condylar guidance angle between the right and left side by both the methods was not statistically significant. The comparison of mean condylar guidance angles between the right side of the protrusive record method and the right side of the panoramic radiographic method and the left side of the protrusive record method and the left side of the panoramic radiographic method ( p= 0.071 and p= 0.057, respectively) were not statistically significant. Conclusion : Within the limitations of this study, it was concluded that the protrusive condylar guidance angles obtained by panoramic radiograph may be used in programming semi‐adjustable articulators.     

Accuracy of check-bite registration and centric condylar position

In a dentate subject a jaw relation can either be determined in maximum intercuspation and is as such given by the occlusal morphology, or the mandibular position can be allocated according to the centric position of the condyles. For comprehensive restorative treatment or analytic measures of the occlusion it is important to record the centric condylar position. Various registration methods have been described in the literature, but there is no consensus on which is the 'best'. The aim of the present study was therefore to assess the accuracy of various registration methods and evaluate a possible influence of the used materials. Four dentists were involved in the clinical part of the study, another was responsible for the measurements. Impressions were taken from 81 fully dentate volunteers. The casts were mounted by face-bow transfer and central-bearing-point (CBP) registration into Dentatus articulators. Subsequently the centric condylar position was determined with six different methods and materials, respectively. Each method was reproduced twice so that a total of 18 registrations was performed per patient. The mandibular positions which resulted from the individual registrations were then repeatedly compared in the condylar area using a computer supported specially modified measuring articulator. The accuracy was found best for the unrefined wax wafer registration (x=0.33 mm) and with an average of 0.44 mm worst when using acrylic wafers. The CBP and frontal jig methods as well as tin-foil and refined wax wafers showed an accuracy in-between these boundaries. The biggest measured mandibular displacement between any two registrations were considerably 2.0 mm. However, the described differences in accuracy between the various methods and materials proved statistically not significant. All investigated jaw registrations showed an accuracy of about 20 times the tactile fine sensibility of natural teeth which has to be taken into account when inserting fixed prosthetic restorations in centric condylar position. Despite meticulous clinical and technical procedures small occlusal adjustments are therefore almost unavoidable.