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Journal of International Society of... 2019The objectives of this study were to determine the condylar guidance by the conventional method using interocclusal records and by panoramic radiographs in healthy...
Comparison of Sagittal Condylar Guidance Determined by Panoramic Radiographs to the One Determined by Conventional Methods Using Lateral Interocclusal Records in the Saudi Arabian Population.
OBJECTIVES
The objectives of this study were to determine the condylar guidance by the conventional method using interocclusal records and by panoramic radiographs in healthy dentate patients and to compare the values obtained from panoramic radiographs with the values obtained by a conventional method.
MATERIALS AND METHODS
Thirty healthy dentulous subjects of either sex with an age range of 20-40 years visiting Jazan University, College of Dentistry, Dental Clinics for replacement of missing teeth or crowns, were selected according to the inclusion criteria. Maxillary and mandibular casts were obtained and mounted on Whipmix 2240 articulator. Right and left lateral interocclusal records were then made in patients by base plate wax (Dentsply truwax baseplate). This record was transferred to articulator, and condylar values were determined. In all the cases, articulator was programmed. Left and right condylar values were also measured on digital radiographs and readings were recorded. Condylar guidance readings obtained from interocclusal records and those obtained from panoramic radiographic images were compared and analyzed statistically using the -test.
RESULTS
The condylar guidance values obtained from the interocclusal record method for both left and right sides were less when compared to the values obtained from tracing the panoramic radiographs (radiographic method). The difference in values of both the methods was highly significant.
CONCLUSION
Although a significant amount of correlation was found between the two methods, better radiographic techniques should be further investigated.
PubMed: 32039080
DOI: 10.4103/jispcd.JISPCD_11_19 -
Medical Principles and Practice :... 2013The aim of this study was to evaluate a possible relationship between preferred chewing side (PCS) and the anterior guidance angle.
OBJECTIVES
The aim of this study was to evaluate a possible relationship between preferred chewing side (PCS) and the anterior guidance angle.
SUBJECTS AND METHODS
Forty dental nurses and technicians, aged 24-46 years, were each given a piece of chewing gum, which they chewed for about 3 min. At 7 regular intervals (every 15 s), they were interrupted by the principal investigator (P.L.) in order to observe on which side of their mouths they had the bolus of chewing gum. Moulds of their jaws were made and the position of the maxillary arch relative to temporomandibular joints was recorded with a facebow and transferred to a semi-adjustable articulator. After mounting the stone casts of each subject, a measure of the anterior guidance angle was taken with an adjustable incisal table.
RESULTS
Of the 40 subjects, 14 (35%) presented a PCS. Among the 14 subjects who preferred a chewing side, there was a correlation between the PCS and a low angulation of teeth constituting the anterior guidance on that side, but this correlation was statistically nonsignificant.
CONCLUSION
In this study, we found that unilateral chewing creates uneven wear on the anterior teeth and changed the anterior guidance angulation.
Topics: Adult; Chewing Gum; Dental Arch; Female; Functional Laterality; Humans; Male; Mastication; Middle Aged; Pilot Projects; Tooth Wear
PubMed: 23948666
DOI: 10.1159/000353466 -
Journal of Indian Prosthodontic Society 2016The aim of this study was to compare the accuracy of the angle made by Frankfort horizontal plane-occlusal plane on maxillary casts, mounted using the respective...
AIM
The aim of this study was to compare the accuracy of the angle made by Frankfort horizontal plane-occlusal plane on maxillary casts, mounted using the respective facebows on Artex Amann Girrbach and Hanau Wide-vue semi-adjustable articulators with cephalometrically derived Frankfort horizontal plane-occlusal plane angle as a control.
SUBJECTS AND METHODS
Maxillary casts of 30 subjects were mounted on Hanau Wide-vue and Artex Amann Girrbach semi-adjustable articulators following facebow transfer using respective facebows. The Frankfort horizontal plane-occlusal plane angles of these casts were measured using Wixey's digital angle gauge. They were also subjected to a lateral cephalogram, and the occlusal cant was measured using RadiAnt DICOM software.
STATISTICAL ANALYSIS
Using Pearson correlation, the accuracy of the angle made by upper member of the articulator and occlusal plane of mounted maxillary casts in each of the articulator was compared to the Frankfort horizontal plane-occlusal plane angle in lateral cephalogram.
RESULTS
A mean difference of 1.9° was found between Hanau Wide-vue articulator and lateral cephalogram and a mean difference of 3.6° was found between Artex Amann Girrbach articulator and lateral cephalogram. Statistically, Pearson correlation value (r) obtained between Hanau Wide-vue and lateral cephalogram was 0.46 and between Artex Amann Girrbach and lateral cephalogram was 0.25.
CONCLUSION
From the statistical value (r) derived, it can be inferred that the Frankfort horizontal plane-occlusal plane angle of the casts articulated on Hanau Wide-vue articulator was more accurate in comparison to that on Artex Amann Girrbach articulator.
PubMed: 27621543
DOI: 10.4103/0972-4052.176525 -
The Journal of Prosthetic Dentistry Jun 2023Occlusal collisions of articulated intraoral digital scans can be corrected by intraoral scanners (IOSs) or dental design software programs. However, the influence of...
STATEMENT OF PROBLEM
Occlusal collisions of articulated intraoral digital scans can be corrected by intraoral scanners (IOSs) or dental design software programs. However, the influence of these corrections on the accuracy of maxillomandibular relationship is unclear.
PURPOSE
The purpose of this clinical investigation was to measure the effect of occlusal collision corrections completed by the IOSs or dental design software programs on the trueness and precision of maxillomandibular relationship.
MATERIAL AND METHODS
Casts of a participant mounted on an articulator were digitized (T710). The experimental scans were obtained by using 2 IOSs: TRIOS4 and i700. The intraoral digital scans of the maxillary and mandibular arches were obtained and duplicated 15 times. For each duplicated pair of scans, a bilateral virtual occlusal record was acquired. Articulated specimens were duplicated and assigned into 2 groups: IOS-not corrected and IOS corrected (n=15). In the IOS-not corrected groups, the IOS software program postprocessed the scans maintaining the occlusal collisions, while in the IOS-corrected groups, the IOS software program eliminated the occlusal collisions. All articulated specimens were imported into a computer-aided design (CAD) program (DentalCAD). Three subgroups were developed based on the CAD correction: CAD-no change, trimming, or opening the vertical dimension. Thirty-six interlandmark distances were measured on the reference and each experimental scan to compute discrepancies by using a software program (Geomagic Wrap). Root mean square (RMS) was selected to compute the cast modifications performed in the trimming subgroups. Trueness was examined using 2-way ANOVA and pairwise comparison Tukey tests (α=.05). Precision was evaluated with the Levene test (α=.05).
RESULTS
The IOS (P<.001), the program (P<.001), and their interaction (P<.001) impacted the trueness of the maxillomandibular relationship. The i700 obtained higher trueness than the TRIOS4 (P<.001). The IOS-not corrected-CAD-no-changes and IOS-not-corrected-trimming subgroups obtained the lowest trueness (P<.001), while the IOS-corrected-CAD-no-changes, IOS-corrected-trimming, and IOS-corrected-opening subgroups showed the highest trueness (P<.001). No significant differences in precision were found (P<.001). Furthermore, significant RMS differences were found (P<.001), with a significant interaction between Group×Subgroup (P<.001). The IOS-not corrected-trimmed subgroups obtained a significantly higher RMS error discrepancy than IOS-corrected-trimmed subgroups (P<.001). The Levene test showed a significant discrepancy in the RMS precision among IOSs across subgroups (P<.001).
CONCLUSIONS
The trueness of the maxillomandibular relationship was influenced by the scanner and program used to correct occlusal collisions. Better trueness was obtained when the occlusal collisions were adjusted by the IOS program compared with the CAD program. Precision was not significantly influenced by the occlusal collision correction method. CAD corrections did not improve the results of the IOS software. Additionally, the trimming option caused volumetric changes on the occlusal surfaces of intraoral scans.
PubMed: 37365066
DOI: 10.1016/j.prosdent.2023.05.015 -
Beijing Da Xue Xue Bao. Yi Xue Ban =... Dec 2020To establish the workflow of determining the jaw position of repositioning splint with the aid of digital technique, and to evaluate the accuracy of this workflow and...
OBJECTIVE
To establish the workflow of determining the jaw position of repositioning splint with the aid of digital technique, and to evaluate the accuracy of this workflow and compare the accuracy of raising different vertical dimensions .
METHODS
A volunteer was recruited. The data of full-arch scans, cone beam computed tomography (CBCT) image and ultrasonic jaw motion tracking of the volunteer were acquired. The full-arch scans were merged with the CBCT image, which were then matched to the jaw motion tracking reference system. The jaw position of repositioning splint was determined when the anterior teeth opening was 3 mm and the condyle was in centric relation of the fossa in the sagittal plane. A digital repositioning splint was designed in the software based on virtual articulator and fabricated with additive manufacturing technique. After the splint was tried in, another CBCT image was taken and a qualitative analysis was conducted to compare the position of condyle between these two CBCT images. In the study, standard dental plaster casts with resin ball markers attached to the base were mounted onto a fully adjustable articulator in the intercuspal position. The dental casts were scanned by an extraoral scanner to establish digital models. The ultrasonic jaw motion tracking device was used to obtain simulated jaw movements on the articulator, which was repeated for three times. The digital models and data of jaw movements were merged in one coordination with the aid of bite forks. The jaw position of repositioning splint was determined by adjusting data of jaw movements, each of which was used to determine three vertical jaw positions 4 mm, 5 mm, and 6 mm with the horizontal jaw position of protrusion 2 mm. The virtual articulators with differently adjusted jaw movements were applied in designing repositioning splints, and the final repositioning splints and virtual jaw relationships were exported in STL format. Then the repositioning splints were fabricated with additive manufacturing technique and tried in plaster casts on the mechanical articulator, which were scanned and the jaw relationships on the mechanical articulator were exported later. The virtual jaw relationships and scanned jaw relationships were registered according to lower models and displacement of upper models was calculated. Ball markers were fit to acquire the coordinates of centers and absolute difference values of centers along three coordinating axes , , and were calculated. One-way analysis of variance was conducted using SPSS 18.0 software to compare deviations of the three different vertical jaw relationships in two-side test and the significance level was 0.05.
RESULTS
With the aid of multi-source data fusion and individualized jaw motion, the clinical workflow of determining jaw position of repositioning splint was preliminarily established. The designed jaw position was realized on the right and the condyle was more inferior than the designed position on the left. Both displacement of the upper models and absolute difference values of centers showed no significant differences (>0.05) in different vertical jaw dimensions. The displacement of the upper models was (0.25±0.04) mm. The absolute difference values of centers along the three coordinating axes , , and were respectively (0.08±0.01) mm, (0.30±0.02) mm, and (0.21±0.04) mm.
CONCLUSION
A novel method of determining the jaw position of repositioning splint with the aid of digital technique is established. It is proved to be feasible by try-in after multi-data fusion, computer-aided design and computer-aided manufacturing. As is shown , it is accurate to apply this method in adjusting jaw position. Further clinical trial will be designed to evaluate its clinical effect.
Topics: Computer-Aided Design; Cone-Beam Computed Tomography; Dental Articulators; Humans; Jaw Relation Record; Occlusal Splints; Software; Splints
PubMed: 33550339
DOI: 10.19723/j.issn.1671-167X.2021.01.012 -
Journal of Prosthodontics : Official... Feb 2021Mounting dental casts in an articulator is an important prerequisite for prosthodontic rehabilitation cases where the design of an accurate static and dynamic occlusion...
Mounting dental casts in an articulator is an important prerequisite for prosthodontic rehabilitation cases where the design of an accurate static and dynamic occlusion is needed. Virtual mounting can be achieved through the superimposition of various 3D images acquired from the hard and soft tissues of the patient. The purpose of this technical report is to describe a digital cross-mounting technique for patients undergoing implant-supported fixed prosthetic treatment. Through the use of face scanning, intraoral scanning, and cone beam computed tomography, this technique enables creation of a 3D virtual patient with occlusal registration in centric relation. Ultimately, the described methodology allows for the fabrication of definitive full-mouth implant-supported fixed prostheses.
Topics: Computer-Aided Design; Cone-Beam Computed Tomography; Dental Articulators; Dental Implants; Humans; Workflow
PubMed: 32865872
DOI: 10.1111/jopr.13247 -
Journal of Indian Society of... Apr 2011The purpose of this study was to quantify some clinical parameters useful as esthetic guidelines when gingival contour is modified and to compare the left and right...
BACKGROUND
The purpose of this study was to quantify some clinical parameters useful as esthetic guidelines when gingival contour is modified and to compare the left and right sides of six maxillary anterior teeth.
MATERIALS AND METHODS
Maxillary casts mounted on an articulator according to the axis orbital plane were photographed from 35 young adults. The angle formed between the gingival line and maxillary midline (GLA) and the distance between the gingival zenith of the lateral incisor and the gingival line were measured (LID) using a flexible protractor and digital vernier caliper, respectively. The asymmetry was evaluated using a paired t test for the left vs right measurements of GLA and LID. The descriptive statistics for GLA and LID were calculated.
RESULTS
The GLA measurements of the left side (86.7°±4.2°) were significantly greater than those of the right side (84.6°±5.4°), and the mean absolute symmetry for GLA was 1.7°±4.4°. The mean LID measurement was 0.920.11.
CONCLUSIONS
The gingival zenith of the canine is apical to the gingival zenith of the incisors (GLA <90°) and the gingival zenith of the lateral incisor is below or on (17%) the gingival line when head is oriented on the axis orbital plane. A directional asymmetry was shown with the right side higher than the left side. Along with the other parameters related to dental esthetics, these clinical parameters may serve as esthetic guidelines and may enable us to obtain a more predictable outcome.
PubMed: 21976837
DOI: 10.4103/0972-124X.84382 -
Journal of Indian Prosthodontic Society 2015The accuracy and reliability of the methods used for programming the semi-adjustable articulators determine the accuracy in occlusion. The current recommended average...
STATEMENT OF PROBLEM
The accuracy and reliability of the methods used for programming the semi-adjustable articulators determine the accuracy in occlusion. The current recommended average settings using the Hanau's formula commonly used by clinicians is questionable, and thus reassessment is needed. This study was carried out to evaluate and compare the lateral condylar guidance: (1) Using the Hanau's formula and the computerized jaw tracking device (Kinesiograph). (2) On the right and left sides using both these methods.
MATERIALS AND METHODS
A total of 20 completely edentulous patients (14 male and 6 females) within 40-60 years of age were selected. Jaw relation was recorded followed by face bow transfer. Extraoral Gothic arch tracing was recorded; three protrusive records were obtained and condylar guidance was calculated. Lateral condylar guidance was then calculated using Hanau's formula, followed by the computerized jaw tracking device. A comparative evaluation was done of the obtained values. The same investigator worked with each of the study participants for the purpose of standardization.
RESULTS
The lateral condylar guidance values obtained using the Hanau's formula ranged from 14 to 17° while those obtained using the computerized K7 jaw tracking device ranged from 8 to 40°. Bennett angle values, obtained using the jaw tracking device and Hanau's formula showed statistically significant differences (P < 0.05) using paired t-test (at 95% confidence interval). Bennett angle values of the right and left sides found using the Hanau's formula were almost similar. Difference in the Bennett angle values of the right and left sides were found using the jaw tracking device. However, this difference was not statistically significant (P > 0.05).
CONCLUSION
Based on the results, dentist and dental technicians should consider reassessing the current recommended average settings and use of the Hanau's formula for programming the semi-adjustable articulators.
PubMed: 26929535
DOI: 10.4103/0972-4052.161566 -
Dentistry Journal Jan 2022With the advent of a digital workflow in dentistry, the inter-occlusal articulation of digital models is now possible through various means. The Cadent iTero intraoral...
With the advent of a digital workflow in dentistry, the inter-occlusal articulation of digital models is now possible through various means. The Cadent iTero intraoral scanner uses a buccal scan in maximum intercuspation to record the maxillomandibular relationship. This in-vitro study compares the occlusion derived from conventionally articulated stone casts versus that of digitally articulated quadrant milled models. Thirty sets of stone casts poured from full arch polyvinyl siloxane impressions (Group A) and thirty sets of polyurethane quadrant models milled from digital impressions (Group B) were used for this study. The full arch stone casts were hand-articulated and mounted on semi-adjustable articulators, while the digitally derived models were pre-mounted from the milling center based on the data obtained from the buccal scanning procedure. A T-scan sensor was used to obtain a bite registration from each set of models in both groups. The T-scan data derived from groups A and B were compared to that from the master model to evaluate the reproducibility of the occlusion in the two groups. A statistically significant difference of the contact region surface area was found on #11 of the digitally articulated models compared to the master. An analysis of the force distribution also showed a tendency for a heavier distribution on the more anterior #11 tooth for the digitally articulated models. Within the limitations of this study, the use of a digitally articulated quadrant model system may result in a loss of accuracy, in terms of occlusion, the further anteriorly the tooth to be restored is located. Care must be taken to consider the sources of inaccuracies in the digital workflow to minimize them for a more efficient and effective restorative process.
PubMed: 35049609
DOI: 10.3390/dj10010011 -
Journal of Pharmacy & Bioallied Sciences Jun 2021Various clinical methods for recording the condylar guidance (CG) are the intraoral check bite method, graphic tracings, and functional recordings. Accuracy of graphic...
BACKGROUND
Various clinical methods for recording the condylar guidance (CG) are the intraoral check bite method, graphic tracings, and functional recordings. Accuracy of graphic tracings is affected by patient-related factors such as neuromuscular control of the individual, stability of record bases as well as stability of recording media. The current recommended average settings using Hanau's formula questionable, and thus reassessment is needed.
PURPOSE
The purpose of this study is to use radiographic technique to determine the lateral CG and compare these values with those obtained using Hanau's formula and to evaluate whether there are differences between the right and left paths of the condyles.
MATERIALS AND METHODS
Twenty completely edentulous patients were selected. Articulator was modified with sectioned protractor for obtaining per degree interval calibration. With the protrusive records, the horizontal CG (H) was adjusted and the Bennett's angle (LCG-C) was calculated using the formula. With the tracing device in the mouth, sub-mento vertex projection radiographs were obtained. Each radiograph was traced and superimposed for Bennett angle determination (LCG-M).
RESULTS
The median (interquartile range [IQR]) of right and left LCG-C were 15.45 (0.8) and 15.50 (0.7), respectively. The median (IQR) of right and left LCG-M were 37.00 (6.0) and 36.50 (6.8), respectively. A statistically significant difference exists between LCG-C and LCG-M. Both LCG-C and-M values exhibited no variations on both sides.
CONCLUSIONS
Radiographic technique yielded an amplified LCG when compared to the value obtained by Hanau's formula.
PubMed: 34447149
DOI: 10.4103/jpbs.JPBS_640_20