Facebow System Research Articles

Intraoral scanner-based virtual facebow transferring: A chairside dental technique.

Accurately mounting dental casts on an articulator is an essential step in prosthetic treatments. In digital dentistry, virtual articulator mounting procedures rely on virtual facebow records. However, virtual facebow records usually require devices like face scanners or jaw motion tracking systems that are not commonly available in most dental practices. The present technique report describes a straightforward intraoral scanner-based virtual facebow transfer approach. In this technique, a reference facebow joint support was first scanned and aligned with a virtual articulator. Then, a patient's facebow joint support and bite fork assembly were scanned chairside with an intraoral scanner and aligned with the virtual articulator by matching common features with the reference facebow joint support. After aligning the patient's intraoral scans with the patient's bite fork scan that was already superimposed on the virtual articulator, a virtual mounting process was achieved. Once the corresponding reference facebow joint supports have been generated, this technique can be easily implemented with most facebow systems and be seamlessly integrated into daily clinical practice as only an intraoral scanner and a conventional facebow were required.

Comparison of TMJ angles based on the ARCUSdigma II examination and occlusion records in the Protar 7 articulator

Introduction. Prosthetic restorations should be adjusted to the patients’ occlusion and articulation. Traditional and modern articulator and face-bow systems that simulate individual jaw movements are used in the treatment. Aim of the study. The aim of the study was to compare the values of TMJ angles based on the ARCUSdigma examination and wax occlusion records in the Protar 7 articulator. Method. The study was conducted on a group of 20 patients aged 23-30 years with full dentition and normal occlusion. The position of the maxilla was recorded with face-bow ARCUSevo. Every patient was examined using ARCUSdigma II device. Cast models of the maxilla and mandible were made and mounted in Protar 7 articulator. Wax occlusion records were taken in intercuspal, protrusive and laterotrusive positions. On their basis TMJ angles were established in the articulator. The sagittal condylar inclination and Bennett angles relative to the Frankfurt plane obtained using electronic measurement and manual settings in the articulator were compared. Results. Mean values of sagittal condylar inclination angles based on occlusion records in Protar 7 articulator amounted to 56.9° on the left and 53.7° on the right side and the ARCUSdigma respectively 58.8° for the left and 55.6° for the right TMJ. According to occlusion records in articulator average Bennett angles were valued 11.2° (left) and 9.7° (right), while ARCUSdigma 8.5° (left) and 7.3° (right). Conclusions. Mean values of sagittal condylar inclination angles determined by the occlusion records in Protar 7 articulator and obtained in the ARCUSdigma examination were different and higher than the average values. Mean values of Bennett angles obtained in an ARCUSdigma examination were lower than using occlusion records in Protar 7 articulator and lower than the average values.

An in vitro evaluation of the maxillary occlusal plane orientation obtained with an electronic application: A preliminary investigation

Statement of problemIn the evaluation and fabrication of dental prostheses, maxillary occlusal plane orientation in the sagittal and coronal planes may affect functional and esthetic outcomes. The accuracy of a recently developed electronic application in transferring this orientation to a semiadjustable articulator has not been evaluated. PurposeThe purpose of this in vitro study was to evaluate the coronal and sagittal orientation of the occlusal plane on maxillary casts mounted with an electronic application facebow system onto a corresponding semiadjustable arcon articulator. Material and methodsA maxillary typodont was placed into a phantom head (control) oriented with the Frankfort horizontal plane parallel to the horizon. A digital protractor was used to measure the angle between the occlusal plane of the maxillary arch of the phantom head and the Frankfort horizontal plane along the sagittal and coronal planes. The commercial system (test group) was used to make 15 facebow records of the maxillary typodont within the phantom head. The system records were used to mount diagnostic casts of the maxillary typodont onto a semiadjustable arcon articulator. The same measurements were made on the mounted diagnostic casts and were compared with the control. Statistical differences between the occlusal plane of the control and the occlusal plane of the mounted maxillary casts were determined using the 1-sample t test (α=.05). ResultsThe coronal orientation of the occlusal plane was significantly different (P<.001) between test group and control. No significant differences (P>.05) were found in the sagittal orientation of the occlusal plane. ConclusionsWithin the limitations of this study, variations in the coronal plane orientation were observed with the system. Variations in this plane may lead to adverse evaluation and clinical outcomes.

Evaluation of Two Facebow/Semi-adjustable Articulator Systems for Orienting Maxillary Cast on Articulators: A Pilot Study.

The present study was aimed to assess the transferability of occlusal plane (OP) orientation from the patient to the articulators with the help of two different facebow systems and evaluated with a gold standard. Twenty dentate patients were selected for the study. Two semi-adjustable arcon articulators that are Hanau Wide(®) Vue using SpringBow and Whip Mix(®) using quick-mount facebow were used in the study. Mean angle between OP to horizontal reference plane obtained from Hanau Wide Vue articulator system (SpringBow using Orbitale as anterior reference point) and Whip Mix articulator system (quickmount facebow using nasion as anterior reference point) was tabulated. These values obtained were further compared with each other and evaluated against cephalometric evidence, which was considered as the gold standard for the study. Descriptive statistics, analysis of variance, Scheffe post hoc analysis for group comparison, and level of significance (P) was calculated using Statistical Package for the Social Sciences version 16 (IBM, New York, USA) software program. Intragroup comparison of mean angle OP values showed highly significant difference (p = 0.000). Comparison between Hanau Wide Vue articulator system and Whip Mix articulator system showed statistically highly significant with a mean difference of 10.51° with Hanau system values being lower than Whip Mix system. Difference between Hanau system and cephalometric values were statistically significant with a mean difference of 2.835° and Hanau system consistently recording lower values than cephalometric values. Difference between Whip Mix system and cephalometric values was also statistically significant with a mean difference of 7.680° with group 2 values were on average 7.680° higher than group 3. Within the limitations of this study, the Hanau system and Whip Mix system showed significant difference in reproduction of angle between OP and horizontal reference plane. Hanau articulator system showed closer values to that of cephalometric values in comparison with Whip Mix articulator system. Orientation of the maxillary cast in an articulator is a crucial part of several techniques used in dentistry. Orientation of maxillary cast in the articulator acts as a baseline from which further steps for occlusal rehabilitation of the patients are carried out. Recording and transferring of the occlusal cant to articulators require facebow.

In vitro comparison of the maxillary occlusal plane orientation obtained with five facebow systems

Statement of problemThe sagittal and coronal orientation of the maxillary occlusal plane plays an important role in the esthetic and functional outcome of dental prostheses. The accuracy of contemporary facebow transfer systems in transferring this orientation to semiadjustable articulators has not been quantified. PurposeThe purpose of this in vitro investigation was to analyze the sagittal and coronal orientation of the occlusal plane with 5 different facebow transfer systems. Material and methodsA phantom head containing a maxillary typodont (control) was oriented so that the Frankfort horizontal plane was horizontal. The angle between the occlusal plane of the maxillary arch of the phantom head and the Frankfort horizontal plane was measured along the sagittal and coronal planes with a digital protractor. Fifteen facebow records using each of 5 facebow transfer systems (test groups) were made on the phantom head containing the maxillary typodont. Diagnostic casts of the maxillary typodont were mounted on semi-adjustable arcon articulators from the facebow records. The same angles measured on the control were measured on the test groups. These angles were compared with the same angle measured on the maxillary arch of the phantom head (control). All measurements were made by 2 operators. ResultsSignificant differences in the sagittal and coronal orientation of the occlusal plane were noted. Compared with the control, the Denar system had the least significant difference in the coronal orientation of the occlusal plane, while the Pana-Mount system had the least significant difference in the sagittal orientation of the occlusal plane. An intergroup comparison of the test groups showed significant differences among the groups. The Kois system showed the greatest difference in the coronal plane orientation, while the Denar system showed the greatest difference in the sagittal plane orientation. ConclusionsNone of the tested facebow systems exactly replicated the sagittal and coronal orientation of the maxillary occlusal plane. Significant differences in the sagittal and coronal orientation of the occlusal plane were observed between the test groups and the control. Intergroup comparisons revealed significant differences in the sagittal and coronal orientation of the occlusal plane.

Evaluation of the inclination of maxillary occlusal plane on mounted casts using a fixed value and customized nasion indicator in artex articulator: Facebow system - An in-vivo comparative study

Aim:To evaluate and compare the variations in the inclination of occlusal plane of casts mounted on Artex articulator using a facebow with a fixed value and customized nasion indicator.Materials and Methods:Twenty two subjects were selected for this investigation. Two maxillary impressions were made, and casts poured. For each of the twenty two subjects, the facebow records were made with, Artex face-bow using a fixed value nasion indicator and customized nasion indicator and mounted. The angle between the occlusal plane of upper cast and the upper articulator arm was measured with a Universal bevel protractor and compared with the gold standard cephalometric value.Results:It shows that, when angle was measured between maxillary occlusal plane and upper member of the articulator, on the mounted cast using a customized nasion indicator and fixed value nasion indicator against the gold standard cephalometric value as a whole, it was found to be not significant. But, if each patient were evaluated individually, there found to be the difference in the angle.Discussion and Conclusion:Variation in occlusal plane was very minimal and close to the cephalometric value when using customized nasion indicator compared to fixed value nasion indicator on the Artex.

Accuracy of two face-bow/semi-adjustable articulator systems in transferring the maxillary occlusal cant

The precision of an arbitrary face-bow in accurately transferring the orientation of the maxillary cast to the articulator has been questioned because the maxillary cast is mounted in relation to arbitrary measurements and anatomic landmarks that vary among individuals. This study was intended to evaluate the sagittal inclination of mounted maxillary casts on two semi-adjustable articulator/face-bow systems in comparison to the occlusal cant on lateral cephalograms. Maxillary casts were mounted on the Hanau and Girrbach semi-adjustable articulators following face-bow transfer with their respective face-bows. The sagittal inclination of these casts was measured in relation to the fixed horizontal reference plane using physical measurements. Occlusal cant was measured on lateral cephalograms. SPSS software (version 11.0, Chicago, IL, USA) was used for statistical analysis. Repeated measures analysis of variance and Tukey's tests were used to evaluate the results (P < 0.05). Comparison of the occlusal cant on the articulators and cephalogram revealed statistically significant differences. Occlusal plane was steeper on Girrbach Artex articulator in comparison to the Hanau articulator. Within the limitations of this study, it was found that the sagittal inclination of the mounted maxillary cast achieved with Hanau articulator was closer to the cephalometric occlusal cant as compared to that of the Girrbach articulator. Among the two articulators and face-bow systems, the steepness of sagittal inclination was greater on Girrbach semi-adjustable articulator. Different face-bow/articulator systems could result in different orientation of the maxillary cast, resulting in variation in stability, cuspal inclines and cuspal heights.

A comparative analysis of optical and conventional axiography for the analysis of temporomandibular joint movements

Statement of problem Currently available systems for pantographic tracing are heavy, bulky, and can interfere with jaw movements. Purpose This study describes the development and clinical application of optoelectronic axiography designed to overcome system inherent problems of conventional bulky frame-based registration axiography. The purpose of this study is the comparison of the newly developed system and conventional axiography. Material and methods Three-dimensional recordings of condylar pathways were acquired by means of infrared digitizers interfaced to newly developed software. Ten distinct curves in each of 10 subjects were recorded by synchronous optoelectronic axiography (100 tracings) and by conventional axiography (100 tracings). Usually, two 3-dimensional (3D) light weight sensors are provisionally fixed to the facial surface of a maxillary and mandibular incisor by means of a single orthodontic bracket. To allow for direct comparison of all 100 pairs of curves in this study, the 3D sensors of the optoelectronic system were attached to the bulky double face-bow system of the axiograph. The conformity of tracings (protrusion, opening/closing, mediotrusion, and laterotrusion) was evaluated by means of correlation analysis. Resulting axiographic recordings from both systems were evaluated by 3 experts (dentists, experienced in axiographic investigations, who were blind to the source of the data), focusing on standardized qualitative criteria of the recordings (homogeneity/smoothness, pathway-characteristics, excursion, and left/right-symmetry). After testing for normal distribution of the ratio scaled data (length of pathway, horizontal condylar inclination [HCI], Bennett angle) with the Kolmogoroff-Smirnov test (α=.01), axiographic curves were quantitatively compared by means of an intraclass correlation coefficient ([ICC] α =.01). The Wilcoxon test (α=.01) was used to evaluate equivalence of ordinally scaled values (homogeneity of tracings) and Cohen's Kappa was used to compare excursion and left/right symmetry. Results High correspondence between curves recorded by conventional and optoelectronic axiography was observed. The mean differences of lengths between the protrusive, opening/closing, and mediotrusive pathways were 0.0 mm, 0.6 mm, and 0.1 mm, respectively. Pathways and values for HCI were found highly correlated (pathways: 95% CI of ICC 0.9776-0.9908; HCI: 95% CI of ICC 0.8641-0.9597). The 95% CIs for differences of pathways, HCI-value, and Bennett angle were −0.1mm/0.3mm, −3.4 degrees/1.9 degrees, and −2.8 degrees/4.8 degrees, respectively. Pathway characteristics also corresponded well (Cohen's Kappa: 0.73 for symmetric and 0.72 for asymmetric movements), 0.77 for left/right symmetry, whereas other characteristics showed less significant correlation (Cohen's Kappa of excursion: 0.21 for symmetric and 0.09 for asymmetric movements, homogeneity: 0.08 for symmetric and 0.15 for asymmetric movements). Conclusion Within the limitations of this study, optoelectronic axiography proved to be an applicable, promising technique, leading to diagnostic interpretations equivalent (with respect to the CIs) to conventional axiography.

A comparative study of two arbitrary face-bow transfer systems for orthognathic surgery planning

The relative reproducibility of two widely used arbitrary face-bow transfer systems, the Denar Slidematic and the Dentatus type AEB, was assessed for use in orthognathic surgery planning. A novel method was also developed to determine any variation in three-dimensional spatial position and orientation of the maxillary cast. This envelope of movement enabled realistic comparisons to be made for each face-bow system, operator, and skeletal type. The overall face-bow/articulator procedure showed poor reproducibility. However, the Denar Slidematic face-bow was better ( P<0.001) than the Dentatus type AEB standard face-bow, and the errors were higher in the anteroposterior and lateral directions than the vertical direction. There was no significant difference between operators for each system.

全上下顎骨同時移動術における顔弓を用いる上顎骨骨片位置決定法

It is very important to reposition and to keep the occlusal plane in harmonious relation to TMJ and the skull in two jaw surgery. In addition, the surgery should be performed as accurately as the presurgical planning.However, it is not always easy to satisfy the above-mentioned items in deformities indicating sagittal, transverse and vertical dysplasia or discrepancy of maxilla and mandible. For this reason, we have performed the method of intra-operative repositioning of the Le Fort I osteotomized maxilla according to the pre-operative planning by using the semi-adjustable articulator SAM or Whip-Mix facebow. We use routinely the simultaneous jaw movement by Le Fort I and sagittal splitting osteotomy for two jaw surgery.The maxillary position determined by preplanning of the cephalometric prediction tracing and model operation is recorded with the facebow. After the recording, the facebow with the bitefork is removed from the articulator, and is sterilized with gas to be ready for the intraoperative transfer.The maxilla is adequately mobilized as usual, the vertical dimensions of maxilla are reduced to the same extent as the model operation. The osteotomized maxilla is inserted into the bite fork. Then, the facebow is adjusted to the external auditory canal.In addition, intermaxillary wiring is performed after the mandible is also inserted into the bitefork. Once the facebow is fixed by the nasion locator, the facebow system is kept rigid and free from distortion.The characteristics or advantages and the indication of this facebow transfer system are as follows:1. This system using the Whip-mix or the SAM facebow guarantees precise transfer from the articulator to the patient.2. It has the possibility of obtaining intra-operatively accurate reproduction of the position of osteotomized maxilla in relation to the skull, the mandibular teeth arch, and the TMJ as preplanned.3. It has the possibility of keeping the transferred position and stabilizing maxilla with the mini-plates without freehanding.4. As this system is a “step by step” technical procedure, the laboratory workup is very important.5. The model operation in this system is for the oral surgeon operation training.6. The indication of this system seems to be facial asymmetry or long face with mandibular protrusion.We have performed this facebow transfer system on 14 patients and obtained good results. All patients currently have acceptable results.