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1.
Gen Dent ; 69(1): 31-36, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33350953

RESUMEN

The objective of this study was to compare techniques of different methods of obtaining centric relation to verify which technique generates the greatest reproducibility of the centric relation. The PubMed/MEDLINE, Cochrane Library, SciELO, Scopus, and Web of Science databases were searched for articles published up to May 15, 2018. The search terms were combinations of "dental centric relation" with each of the following terms (individually): "reproducibility of findings"; "jaw relation record"; "chin point"; "gothic arch"; "bimanual manipulation"; "swallowing"; and "jig." The inclusion criteria included clinical studies in English that had to compare at least 2 techniques representing different methods for obtaining centric relation (based on the reproducibility of the centric relation) in individuals without temporomandibular dysfunction; and studies performed in individuals with complete or nearly complete dentition or complete edentulism. Methods (techniques) included in this study were guided methods (chin point guidance and bimanual manipulation); graphic methods (intraoral and extraoral gothic arch tracing); and physiologic methods (swallowing and tongue retrusion along the palate). A total of 1638 articles were identified. After the inclusion and exclusion criteria were applied, 7 articles were included in this review. None of the reviewed studies evaluated edentulous individuals. Two articles compared physiologic methods with guided methods; one concluded that the swallowing technique generates greater variability than guided methods, and the other concluded that there was no difference between the swallowing technique and chin point guidance. Of 5 articles comparing intraoral gothic arch tracing with guided methods, 2 showed similar results between different methods, 2 showed superior results for gothic arch tracing, and 1 showed superior results for the guided methods. Based on the guided methods and swallowing technique, it is not possible to conclude which technique can generate the greatest reproducibility of the centric relation. It is possible to suggest that in most cases intraoral gothic arch tracing is superior or equivalent when compared to guided methods.


Asunto(s)
Boca Edéntula , Relación Céntrica , Humanos , Registro de la Relación Maxilomandibular , Reproducibilidad de los Resultados
3.
Int J Prosthodont ; 33(4): 380-385, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32639697

RESUMEN

PURPOSE: To test the accuracies of different methods of digital vertical dimension augmentation (VDA) by comparison with a clinical situation. MATERIALS AND METHODS: Bite registrations with approximately 5 mm of VDA were made in the incisor regions of 10 subjects (mean VDA 4.5 mm). The conventional maxillary and mandibular stone casts in maximum intercuspation (MICP) and VDA bite registrations were digitized for all subjects using a laboratory scanner (control group). Lateral portraits were taken of all subjects to locate the position of the condylar axis. Four different digital VDA methods were compared to the control group: 100% rotation of the mandible referring to the lateral picture (100RL); 85% rotation and 15% translation referring to the lateral picture (85R15TL); 100% rotation in normal mounting mode of the Trios virtual articulator (100R); and jaw-motion analysis (JMA) equipment. The amount of VDA for each experimental group was compared to the control group. The augmented distances between the central incisors and the second molars were measured using 3D analyzing software. The ratio of the augmented distances between the posterior and anterior regions (P/A ratio) was calculated. One-way analysis of variance and multiple comparisons via least significant difference test were carried out to determine statistical significance. RESULTS: The P/A ratio of each group was as follows: Control = 0.61; 100RL = 0.55; 85R15TL = 0.61; 100R = 0.53; JMA = 0.52. Significant differences were observed for control vs JMA and for 85R15TL vs JMA (P < .05). The addition of translational movement was the primary factor for increasing the accuracy of digital VDA, with the lateral picture being a secondary factor. CONCLUSION: VDA using a virtual articulator with 100% rotation induces an error when compared to the clinical situation. When a clinician performs digital VDA, the setting of 85% rotation and 15% translation produces results closer to the real clinical condition.


Asunto(s)
Articuladores Dentales , Modelos Dentales , Registro de la Relación Maxilomandibular , Mandíbula , Proyectos Piloto , Dimensión Vertical
4.
Int J Comput Dent ; 23(1): 17-26, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32207458

RESUMEN

When recording condylar movement paths with the aid of electronic measuring systems, it is often found that, especially in jaw opening and closing movements, excursive and incursive paths of movement are not congruent but run separately, independently of one another to a greater or lesser degree. The objective of the study was to investigate this phenomenon in the context of rotation vs translation behavior, also taking into consideration additional side-specific condylar movement patterns. For this purpose, the electronic movement records of habitual jaw opening of 259 participants of the associated project of the population-representative basic study SHIP 0 were evaluated. The condylar movement path (condylar tracing, ConTrac) at the arbitrary axis point, the excursion vs incursion behavior in the condylar tracing grid (ExInGrid), and the rotation vs translation behavior (RotTrans) were classified, and the translational condylar path and the maximum angle of rotation were determined metrically. Relationships between the parameters ConTrac, ExInGrid, and RotTrans were statistically analyzed using cross tabulations and Spearman's correlation coefficient. Only about 18% of ConTrac showed congruence of excursive and incursive movement path components, while 39% demonstrated noncongruent paths, and 43% showed further conspicuous features in the movement path. For the parameter ExInGrid, recognizable to highly pronounced loop formation patterns to a degree of 89% were observed in the condylar tracing grid. An average of 12.5 mm (min 2.1 mm, max 21.7 mm) was determined for the purely translational component of the condylar movement path, and 32.1 degrees (min 12 degrees, max 45 degrees) for the maximum angle of rotation. Concerning the rotation vs translation behavior, the linear basic pattern occurred at around 9%; the sigmoidal pattern at 28%; and the hysteretic, loopy or irregular pattern at 63%. The parameters RotTrans and ExInGrid showed a strong correlation, whereas the strength of the correlation for ConTrac and ExInGrid or RotTrans and ConTrac was evaluated as weak or very weak. The rotation vs translation behavior influences condylar movement paths in the positional relationship of excursive and incursive components. The visualization of several condylar movement paths in the form of a condylar tracing grid helps to capture complex rotational and translational motion components of the real condyles more effectively than the assessment of a single condylar movement path.


Asunto(s)
Mandíbula , Cóndilo Mandibular , Humanos , Registro de la Relación Maxilomandibular , Movimiento , Rotación , Articulación Temporomandibular
5.
Int J Comput Dent ; 23(1): 39-48, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32207460

RESUMEN

BACKGROUND: The Dental Motion Decoder system (DMS-System) is a medical device based on magnetic field technology that records mandible movements. The data can be used to program an articulator or can be directly processed over a computer-aided design (CAD) interface. The present study aimed to assess the reproducibility of this system in vitro and in vivo. MATERIAL AND METHODS: Protrusive and laterotrusive movements were simulated in vitro using an articulator (SAM SE) (Group M) and in vivo (Group P) on one test individual. Measurements were carried out in two ways: 1) Measurements were taken after initializing and referencing the system using the reference points (RPs) once, followed by 30 protrusive and laterotrusive movements (M1 and P1); and 2) Thirty individual measurements were recorded using the RPs before each measurement (M2 and P2). Values for the sagittal condylar path inclination angle (sCPIA) and the Bennett angle (BA) were exported and analyzed. The reproducibility of the system was evaluated using the standard deviations (SDs) of the measurement series (sCPIA and BA for M1, M2, P1, and P2). RESULTS: In vitro tests M1 (SD: sCPIA = 0.08 degrees; BA = 0.06 degrees) and M2 (SD: sCPIA = 0.26 degrees; BA = 0.11 degrees) showed significantly higher reproducibility (P < 0.001) compared with the in vivo measurements P1 (SD: sCPIA = 0.61 degrees; BA = 0.45 degrees) and P2 (SD: sCPIA = 1.4 degrees; BA = 0.65 degrees). CONCLUSION: Within the limitations of the present study, the deviation in vitro, representing the reproducibility of the DMD-System, is smaller than the biologic variance observed in vivo. Therefore, reliable measurements under clinical conditions can be assumed.


Asunto(s)
Articuladores Dentales , Cóndilo Mandibular , Humanos , Registro de la Relación Maxilomandibular , Imanes , Movimiento , Reproducibilidad de los Resultados
6.
Beijing Da Xue Xue Bao Yi Xue Ban ; 52(1): 138-143, 2020 Feb 18.
Artículo en Chino | MEDLINE | ID: mdl-32071477

RESUMEN

OBJECTIVE: To evaluate the three-dimensional (3D) reconstruction accuracy of the intercuspal occlusion (ICO) of the dental casts, by the dental articulator position method, and provide a reference for clinical application. METHODS: The standard dental casts in ICO were mounted on average values articulator, and five pairs of milling resin cylinders were respectively attached to the base of both the casts. 100 µm articulating paper and occlusal record silicone rubber were used to detect the occlusal contact number between the posterior teeth of casts mounted on articulator in ICO. The occlusal contact numbers NA detected by the two methods were calculated simultaneously, as the reference. After the upper and lower casts were scanned separately, and the buccal data of casts in ICO were scanned with the aid of the dental articulator position, registration was carried out utilizing the registration software. Then the digital casts mounted in ICO as well as the buccal occlusal data were saved in standard tessellation language (STL) format. Geomagic Studio 2013 software was used to analyze the contact number NS between digital upper and lower casts by the "deviation analysis" function. The differences were compared between NS and NA, to evaluate the sensitivity and positive predict value (PPV) of the model scanner to reproduce the occlusal contact with the aid of dental articulator position. The distance DR between the centers of the circles at the top surface of the upper and lower corresponding cylinders was obtained by the three-coordinate measuring system Faro Edge, as the reference value. The Geomagic Studio 2013 software was used to construct the cylinders of digital casts and the distance DM between the centers of the circles at the top surface of the corresponding cylinders were measured, as the test value. The one-sample T test was used to analyze the variable differences between DM and DR. RESULTS: The PPV of reproducing the occlusal contact point was 0.76 and sensitivity was 0.81. The distance error of the opposite cylinder was (0.232±0.089) mm. There was no statistical difference between the feature points 5-5', while there were statistical differences between the other feature points. CONCLUSION: By the dental articulator position method, the model scanner reproduces the occlusal contact point with high sensitivity and PPV, and that meets clinical needs. Meanwhile, the distance between the feature points is greater than the reference value, which will lead to occlusal disturbance, and require clinical grinding.


Asunto(s)
Articuladores Dentales , Modelos Dentales , Oclusión Dental , Imagenología Tridimensional , Registro de la Relación Maxilomandibular , Programas Informáticos
8.
J Prosthodont ; 29(2): 185-189, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31919939

RESUMEN

The articulator is a prerequisite device for the analysis of occlusion and prosthodontic treatment, and it is required to simulate patient jaw movements. This article describes the technique to obtain sagittal condylar inclination (SCI) using cone beam computed tomography (CBCT) data and intraoral scan of the protrusive interocclusal position. The SCI can be used on a virtual articulator in a computer-aided design software, and it can assist in the fabrication of prosthesis which is harmonious with the mandibular movement of individual patient.


Asunto(s)
Tomografía Computarizada de Haz Cónico , Articuladores Dentales , Diseño Asistido por Computadora , Oclusión Dental , Humanos , Imagenología Tridimensional , Registro de la Relación Maxilomandibular , Mandíbula , Cóndilo Mandibular
9.
J Prosthodont ; 29(1): 19-25, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31270888

RESUMEN

PURPOSE: To determine the reliability of T-scan and 3D intraoral scan techniques for assessing the occlusal contact area (OCA), compared to occlusal registration and also to assess the validity of the techniques. MATERIALS AND METHODS: Thirty-one dentate adults participated in this cross-sectional study. T-scan records were used to measure the OCA at maximum bite force and at 50% of maximum force using the software's bite force selection tool. A second method measured the OCA between 2 virtual models scanned intraorally using a 3D surface scan and considering the occlusal contact at 2 interocclusal distances (0-100 and 0-200 µm). The third method measured OCA using occlusal registration at moderate and maximum occlusal force, and considering contact at the 2 interocclusal distances (0-100 and 0-200 µm). Images obtained using the 3 methods were analyzed using ImageJ software. Test-retest reliability was assessed by the intraclass correlation coefficient (ICC) and validity by Pearson correlations. RESULTS: ICCs ranged from 0.56 to 0.79 (p < 0.001) for the T-scan; 0.37 to 0.61 (p < 0.05) for 3D surface scan; and 0.92 to 0.95 (p < 0.0005) for occlusal registration. The highest OCA values were obtained using the T-scan, and the lowest using the 3D surface scan. Occlusal registration measurements had the highest correlations with those of the other techniques. CONCLUSIONS: T-scan is a reliable method for measuring the OCA, but the 3D surface scan is not. Occlusal registration showed a high validity.


Asunto(s)
Oclusión Dental , Imagenología Tridimensional , Adulto , Fuerza de la Mordida , Estudios Transversales , Humanos , Registro de la Relación Maxilomandibular , Reproducibilidad de los Resultados
10.
J Prosthet Dent ; 123(2): 299-304, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31227235

RESUMEN

STATEMENT OF PROBLEM: The optimal procedure for the transfer of the sagittal inclination of the occlusal plane (OP) to semiadjustable and fully adjustable articulators is unclear. PURPOSE: The purpose of this clinical study was to evaluate and compare the sagittal inclination of the OP with the Frankfort horizontal plane (FHP) on a facebow transfer to semiadjustable and fully adjustable articulators. MATERIAL AND METHODS: Facebow transfers (Hanau Spring-Bow; Whip Mix Corp) of 30 participants were recorded and transferred to a semiadjustable articulator (Hanau Wide-Vue; Whip Mix Corp) using the indirect method. Another set of facebow transfers from the same set of 30 participants using another facebow (Denar Slidematic Facebow; Whip Mix Corp) was recorded and transferred to a fully adjustable articulator (Denar D5A; Whip Mix Corp). The angle between the OP of the mounted cast and the upper member of the articulator was measured in each participant with a digital protractor on both articulators. Standardized lateral cephalograms of each participant were made as a control. The FHP and OP were traced on each standardized lateral cephalogram. The angle on the cephalogram between the FHP and OP was measured. These values were compared with previously measured values for the Hanau Wide-Vue and the Denar D5A articulators. The data were analyzed using ANOVA. Intergroup comparisons between and among the Hanau Wide-Vue, Denar D5A, and lateral cephalograms were performed using the independent t test. RESULTS: No statistically significant difference was found between the Hanau Wide-Vue and Denar D5A articulators compared with the lateral cephalograms (P=.06). In the intergroup comparison, no statistically significant differences were found between the Hanau Wide-Vue and Denar D5A articulators (P=.18). No statistically significant differences were found between the values obtained on the Hanau Wide-Vue and lateral cephalograms (P=.06). When the Denar D5A articulator was compared with the lateral cephalograms, there was a statistically significant difference (P=.02). CONCLUSIONS: The Hanau Wide-Vue articulator most closely replicated the inclination of the OP. Regarding the sagittal inclination of the OP, the semiadjustable articulator can provide more accurate results than a fully adjustable articulator and thus eliminates occlusal errors.


Asunto(s)
Articuladores Dentales , Oclusión Dental , Aparatos de Tracción Extraoral , Cabeza , Humanos , Registro de la Relación Maxilomandibular
11.
J Prosthet Dent ; 123(2): 305-313, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31227241

RESUMEN

STATEMENT OF PROBLEM: Complex digital workflows have been developed to create virtual dental patients. Direct and indirect digital methods are available for transferring analog patient information to virtual articulators. The direct method consists solely of digital workflows. The indirect method combines analog steps and digital procedures, representing an intermediate solution between the analog and direct digital approach. Studies that have investigated the overall accuracy of the virtual working space are sparse. PURPOSE: The purpose of this clinical study was to investigate the accuracy of the virtual dental space using the indirect digital workflow. MATERIAL AND METHODS: Mounted gypsum casts of 18 patients were used for indirect scanning. The maxillary casts were mounted in their skull-related position with a kinematic facebow. The mandibular casts were mounted in centric relation to the maxillary casts. The obtained digitized casts were transferred to a virtual articulator. An occlusal analysis was performed both in the analog and virtual environments, and the coordinates of matching analog and virtual contact points were measured. The trueness and precision of the indirect transferring procedure were assessed. RESULTS: A total of 194 analog points was considered in the reference. Ninety-three percent of all analog points matched a virtual correspondent, and 96% of the analog first contacts between the casts were also present as first contacts in the virtual space. The trueness of the data transfer, corresponding to the spatial distance between the matching analog and virtual points, was 0.55 ±0.31 mm. The maximum recorded deviation was 1.02 mm. CONCLUSIONS: The correspondence between the number and position of analog and virtual contacts was high. The mean absolute deviation of the matching point-pairs was better than that reported for the direct digital method. Under the conditions described, the virtual dental space created with the indirect digital method can be reliably used for virtual occlusal analysis in clinical practice.


Asunto(s)
Articuladores Dentales , Modelos Dentales , Humanos , Registro de la Relación Maxilomandibular , Mandíbula , Maxilar
12.
J Prosthet Dent ; 123(1): 45-49, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31079888

RESUMEN

With the transition to digital workflows, moving from a digital platform to an articulator for laboratory procedures such as adding porcelain or luting titanium abutments is sometimes required. This report describes a technique to facilitate the transfer of jaw-relation records to a digital mounting template. Once digitally mounted, the casts can be printed with mounting plates attached to the temporomandibular joints in the appropriate orientation. They can then be placed in an articulator and used for layering porcelain or luting titanium abutments for screw-retained restorations.


Asunto(s)
Prótesis Dental de Soporte Implantado , Flujo de Trabajo , Diseño Asistido por Computadora , Porcelana Dental , Registro de la Relación Maxilomandibular
13.
Int J Comput Dent ; 23(4): 363-375, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33491932

RESUMEN

A hands-on method for instrument-based occlusal analysis with digital technology is presented using a patient case example. The method is based on new software for digital occlusal analysis that includes a new measuring system for recording mandibular function (Jaw Motion Analyser Optic System/oJMA). With the new system, occlusal contact patterns in the real movement function of the mandible are captured and analyzed digitally with regard to occlusal interferences or a suitable therapeutic position of the mandible. For this purpose, scans of both jaws are brought together with the movement recordings by means of a special coupling tray and then visualized together as one complete image. Since the movement paths of the temporomandibular joints (TMJs) are also captured, the new system makes it possible to define a suitable therapeutic position specifically aimed at relieving the TMJs, and a therapeutic change in the jaw relation can be adjusted, for instance, by using an occlusal splint. Dedicated software modules provide a layer-by-layer analysis of the intercuspation relationship and the generation of 'envelopes' for occlusal gliding movements. This system is used to gain a deeper and more comprehensive understanding of the relationship between the structure and function of the occlusion. Interfaces to CAD software have also been established.


Asunto(s)
Oclusión Dental , Mandíbula , Humanos , Registro de la Relación Maxilomandibular , Movimiento , Ferulas Oclusales , Articulación Temporomandibular
14.
Beijing Da Xue Xue Bao Yi Xue Ban ; 53(1): 76-82, 2020 Dec 21.
Artículo en Chino | MEDLINE | ID: mdl-33550339

RESUMEN

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 in vitro. 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 in vitro 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 X, Y, and Z 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 (P>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 X, Y, and Z 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 in vitro, it is accurate to apply this method in adjusting jaw position. Further clinical trial will be designed to evaluate its clinical effect.


Asunto(s)
Tomografía Computarizada de Haz Cónico , Férulas (Fijadores) , Diseño Asistido por Computadora , Articuladores Dentales , Humanos , Registro de la Relación Maxilomandibular , Ferulas Oclusales , Programas Informáticos
15.
Int J Comput Dent ; 22(4): 353-362, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31840143

RESUMEN

The articulation parameters, especially the horizontal condylar inclination angle (HCI), the Bennett angle (BA), and the immediate side shift (ISS) were determined in 259 subjects (100 males; 159 females) of the associated project with reference to the population-representative baseline study (Study of Health in Pomerania, SHIP 0). The evaluations were based on a clinical functional status and electronic motion recording with the ultrasonic measuring system Jaw Motion Analyser (JMA, Zebris, Isny, Germany). The reference plane, to which all measured values were represented and the HCI calculated, was the hinge axis infraorbital plane (HA-IOP). The HCI was determined after an excursive movement with a length of 4 mm to the HA-IOP in the sagittal view and the BA after a mediotrusive excursion movement of 6 mm in the horizontal view to the midsagittal plane. For the standard and limit values, the average value in addition to the standard deviation and the 10th and 90th percentile value (10th percentile value, 90th percentile value) were determined: HCI right 52.1 ± 10.14 degrees (39.4 degrees, 64.0 degrees), HCI left 53.1 ± 9.67 degrees (42.3 degrees, 67.0 degrees), BA right 15.2 ± 7.53 degrees (6.7 degrees, 25.0 degrees), BA left 14.2 ± 7.84 degrees (5.4 degrees, 24.1 degrees). The HCI was approximately 2 to 3 degrees larger in females (males: right 50.5 ± 9.47 degrees, left 51.9 ± 8.99 degrees; females: right 53.1 ± 10.42 degrees, left 53.8 ± 10.03 degrees). Likewise, the BA in the age group ≥ 40 years (males: right 14.4 ± 6.62 degrees, left 13.1 ± 7.14 degrees; females: right 17.0 ± 9.02 degrees, left 16.9 ± 8.72 degrees). The latter proved to be statistically significant in the t test for independent samples, assuming variance equivalence on the right, with P = 0.009, and with rejection of the variant equivalence on the left, with P = 0.002. The right and left HCI and BA joint values showed highly significant linear dependence at P < 0.001, but rather low, however, for the HCI with r2 = 0.175 for the HCI and r2 = 0.228 for the BA. In 46% of cases, the right and left HCI values differed up to 5 degrees only; a further 20.9% were in an interval difference of between 5 and 10 degrees. The following results were shown for the differences in the BA: 56.4% of the cases were between 0 and 5 degrees, and 26.2% were in the interval ranges of 5 to 10 degrees. ISS occurred in 18.1% of cases on the right side of the joint, and in 27.8% of cases on the left side. On both sides of the joint it was significantly more frequent in the age group ≥ 40 years with assumed variance equality than in the age group < 40 years (P = 0.002 right, P = 0.003 left). The groups relating to the Helkimo index (HI) did not differ significantly in all function-specific parameters. If it is assumed that there is no significant influence on the occlusion if the HCI values differ by 7 to 8 degrees from the average value, only approximately one third of all cases (35.1%) were characterized by a purely average value setting in the articulator. In 41.7% of cases, one joint value was situated outside the average value range; in 23.2% of the cases both values were outside the average value range. Without a measurement of the condylar path inclination, however, it is impossible to decide to what extent the HCI deviates from the average value, and which joint side is larger or smaller than the other and to what extent. These results suggest that in extensive and complex cases, the articulator should be adjusted according to individual, function-specific joint values.


Asunto(s)
Cóndilo Mandibular , Articulación Temporomandibular , Femenino , Alemania , Humanos , Registro de la Relación Maxilomandibular , Masculino , Rango del Movimiento Articular
16.
Prim Dent J ; 8(3): 40-47, 2019 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-31666172

RESUMEN

An accurate interocclusal record is essential for the successful delivery of fixed prosthodontic restorations. There are various materials and techniques used to obtain an interocclusal record in order to facilitate mounting of the dental casts on an articulator. The interocclusal record describes the vertical and horizontal relationship of the maxillary and mandibular teeth. In circumstances where the vertical relationship is not supported through a tripod of widely spaced opposing contacts, the interocclusal record will be needed to restore this vertical support to prevent inaccurate mounting. The clinician should understand when an interocclusal record is required and have an awareness of the different materials and techniques available to record an interocclusal registration.


Asunto(s)
Articuladores Dentales , Modelos Dentales , Oclusión Dental , Dentición , Registro de la Relación Maxilomandibular , Arcada Parcialmente Edéntula , Prostodoncia , Atención Odontológica , Diseño de Dentadura , Humanos , Registro de la Relación Maxilomandibular/instrumentación , Registro de la Relación Maxilomandibular/métodos
17.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 54(8): 515-521, 2019 Aug 09.
Artículo en Chino | MEDLINE | ID: mdl-31378028

RESUMEN

Occlusal splint is a removable device for the treatment of oral and maxillary diseases with reversible occlusal treatment property. When patients wear the occlusal splint, the occlusal contact state can be changed and the position of the lower jaw may be adjusted, with the improvement of functions of temporomandibular joints and masticatory muscles. There are various types of occlusal splints, among which stabilization splint, soft occlusal splint and repositioning splint are widely used in the treatment of temporomandibular disorders and night bruxism. For the patients requiring occlusal reconstruction, occlusal splint can be used as an important means to adjust and verify the therapeutic jaw position. As a major trend of research in future, the digital design and production of occlusal splint are still in the initial stage and need to be further improved.


Asunto(s)
Ferulas Oclusales , Bruxismo del Sueño , Trastornos de la Articulación Temporomandibular , Humanos , Registro de la Relación Maxilomandibular , Músculos Masticadores , Bruxismo del Sueño/terapia , Trastornos de la Articulación Temporomandibular/terapia
18.
J Appl Clin Med Phys ; 20(10): 24-32, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31460704

RESUMEN

The purpose of this study was to investigate the potential advantages of the fixed-jaw technique (FJT) over the conventional split-field technique (SFT) for cervical and upper thoracic esophageal cancer (EC) patients treated with intensity-modulated radiotherapy. The SFT and FJT plans were generated for 15 patients with cervical and upper thoracic EC. Dosimetric parameters and delivery efficiency were compared. An area ratio (AR) of the jaw opening to multileaf collimator (MLC) aperture weighted by the number of monitor units (MUs) was defined to evaluate the impact of the transmission through the MLC on the dose gradient outside the PTV50.4, and the correlation between the gradient index (GI) and AR was analyzed. The FJT plans achieved a better GI and AR (P < 0.001). There was a positive correlation between the GI and AR in the FJT (r = 0.883, P < 0.001) and SFT plans (r = 0.836, P < 0.001), respectively. Moreover, the mean dose (Dmean ), V5Gy -V40Gy for the lungs and the Dmean , V5Gy -V50Gy for the body-PTV50.4 in the FJT plans were lower than those in the SFT plans (P < 0.05). The FJT plans demonstrated a reduction trend in the doses to the spinal cord PRV and heart, but only the difference in the heart Dmean reached statistical significance (P < 0.05). The FJT plans reduced the number of MUs and subfields by 5.5% and 17.9% and slightly shortened the delivery time by 0.23 min (P < 0.05). The gamma-index passing rates were above 95% for both plans. The FJT combined with target splitting can provide superior organs at risk sparing and similar target coverage without compromising delivery efficiency and should be a preferred intensity-modulated radiotherapy planning method for cervical and upper thoracic EC patients.


Asunto(s)
Neoplasias Esofágicas/radioterapia , Maxilares/fisiología , Órganos en Riesgo/efectos de la radiación , Mejoramiento de la Calidad , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada/normas , Neoplasias Torácicas/radioterapia , Anciano , Algoritmos , Humanos , Maxilares/efectos de la radiación , Registro de la Relación Maxilomandibular , Persona de Mediana Edad , Pronóstico , Dosificación Radioterapéutica , Radioterapia de Intensidad Modulada/métodos
19.
J Contemp Dent Pract ; 20(6): 732-737, 2019 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-31358718

RESUMEN

AIM: In this study, we intend to compare the linear dimensional changes of interocclusal recording media by immersing them in disinfectant solutions at different time intervals. MATERIALS AND METHODS: Five interocclusal recording materials were used for this study and were grouped according to material types, namely wax, zinc oxide eugenol impression paste, polyether, polyvinyl siloxane, and bisacryl bite registration material. Each material was manipulated and injected into a stainless steel die. The materials were divided into 5 groups with 5 subgroups of 10 samples with a total of 250 samples. The samples were subjected to immersion in 2% glutaraldehyde and 0.5% sodium hypochlorite each for 30 and 60 minutes. Linear dimensional changes of the samples were tested by measuring the distance between points A and B at different time intervals by means of a stereomicroscope and compared with the control group. RESULTS: Bisacryl showed the least linear dimensional change when immersed in both the solutions. CONCLUSION: Bisacryl (Luxabite) presented no linear dimensional change at both time intervals as opposed to the other materials, hence, it is most accurate.


Asunto(s)
Desinfectantes , Materiales de Impresión Dental , Registro de la Relación Maxilomandibular , Polivinilos , Hipoclorito de Sodio , Cemento de Óxido de Zinc-Eugenol
20.
Angle Orthod ; 89(6): 924-929, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31232603

RESUMEN

OBJECTIVES: To evaluate condylar movement during lateral excursion in individuals with internal derangement of the temporomandibular joint (TMJ) using ultrasonic axiography. MATERIALS AND METHODS: A total of 34 patients with internal derangement of the TMJ and 34 participants in the control group were examined. Mandibular functional movement was recorded by ultrasonic axiography. Three-dimensional condylar movement was measured in the working and balancing condyles. RESULTS: Significant differences in condylar movement were found between the two groups. In the group with internal derangement of the TMJ, the three-dimensional linear distances of the condylar path in a working condyle were greater than in the control group during lateral excursion. The speed of the balancing condyle in the returning path of lateral excursion was significantly greater in the group with internal derangement than in the control group. CONCLUSIONS: The results of the present study indicate that internal derangement of TMJ may affect the working and balancing condylar movements during lateral excursion.


Asunto(s)
Luxaciones Articulares , Cóndilo Mandibular , Humanos , Registro de la Relación Maxilomandibular , Movimiento , Rango del Movimiento Articular , Articulación Temporomandibular , Ultrasonido
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