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Beijing Da Xue Xue Bao. Yi Xue Ban =... Feb 2024To compare the trueness of incisal guidance of implant-supported single crowns designed by patient-specific motion (PSM) with that designed by average-value virtual...
OBJECTIVE
To compare the trueness of incisal guidance of implant-supported single crowns designed by patient-specific motion (PSM) with that designed by average-value virtual articulator (AVA).
METHODS
The study had recruited 12 participants with complete dentition and stable incisal guidance. An intraoral scanner was used to scan digital casts and record two types of patient-specific motion (data only including protrusive movement, and data including protrusive movement and lateral protrusive movement). The lingual surfaces of the maxillary incisors which guided the protrusive movement was selected and elevated to create a reference cast. A maxillary central incisor of original casts was vir-tually extracted and implanted to generate a working cast. The Dental system software program was used to design implant-supported single crowns with the anatomical coping design method. The incisal guidance was designed by different methods. The incisal guidance in control group was designed by the average-value virtual articulator. The incisal guidance in experiment groups was designed by the patient-specific motion only including protrusive movement (PSM1) and with the patient-specific motion including protrusive movement and lateral protrusive movement (PSM2). The incisal guidance of prosthesis designed by these 3 methods were compared with the original incisal guidance in Geomagic Control 2015 (3DSystem, America). The measurements included: Average of positive values, ratio of positive area and maximum value reflecting supra-occlusion; average of negative values, ratio of negative area and minimum value reflecting over-correction; and root mean square reflecting overall deviation.
RESULTS
Statistical data were collected using the median (interquartile range) method. The average of positive values, ratio of positive area and average of negative values of the PSM2 group were smaller than those of the control group [8.0 (18.8) μm . 37.5 (47.5) μm; 0 . 7.2% (38.1%); -109.0 (63.8) μm .-66.5 (64.5) μm], and the ratio of negative area of PSM2 group was larger than those of the control group [52.9% (47.8%) . 17.3% (45.3%)], with significant differences ( all < 0.05). The ratio of positive area [0.1% (7.0%)] and average of negative values [-97.0 (61.5) μm] of PSM1 group, were smaller than those of the control group, and the ratio of negative area [40.7% (39.2%)] of the PSM1 group was larger than that of the control group, with significant differences ( < 0.05). The average of positive values [20.0 (42.0) μm] and ratio of positive area of PSM1 group was larger than that of the PSM2 group with significant differences ( < 0.05).
CONCLUSION
To establish the incisor guidance of implant-supported single crowns, compared with the average-value virtual articulator and the patient-specific motion only including protrusive movement, the patient-specific motion including protrusive movement and lateral protrusive movement is more conducive to reducing the protrusive interference of prosthesis and improving the occlusal fit.
Topics: Humans; Incisor; Software; Maxilla; Crowns; Movement; Computer-Aided Design
PubMed: 38318900
DOI: 10.19723/j.issn.1671-167X.2024.01.013 -
Journal of Pharmacy & Bioallied Sciences Feb 2024This research study aimed to evaluate and compare the capability of four various bite registration materials to reproduce precise interocclusal relationships in the...
BACKGROUND
This research study aimed to evaluate and compare the capability of four various bite registration materials to reproduce precise interocclusal relationships in the vertical dimension.
MATERIALS AND METHODS
Ideal maxillary and mandibular casts were mounted on the semi-adjustable articulator in maximum intercuspation after mock tooth preparation on 46, 47, and 48. Models were scanned by the Medit T500 Dental Lab Scanner, and initial reading was noted at the predetermined points. Ten interocclusal bite registrations were made using four materials (CADbite, Jet Bite, Ramitec, and Aluwax). The mandibular model was demounted and again remounted using the interocclusal records, and the final reading was noted after scanning.
RESULTS
Ramitec showed superior results when compared to polyvinyl bite registration material and Aluwax, but the differences between Ramitec, CADbite, and Jet Bite were nonsignificant.
CONCLUSIONS
Although all four materials are suitable for clinical use, elastomeric materials showed superior results. In that, polyether was found to be the best.
PubMed: 38595573
DOI: 10.4103/jpbs.jpbs_990_23 -
Computer Methods in Biomechanics and... Jul 2020The location of the terminal hinge axis of the temporomandibular joint is still a very wide-spread procedure in dentistry in order to replicate the movement in various...
The location of the terminal hinge axis of the temporomandibular joint is still a very wide-spread procedure in dentistry in order to replicate the movement in various articulator devices. Especially pantographic methods are claimed to provide accurate measurements and, additionally, are seen to be able to separate a pure rotation of the joint from a movement with an arbitrary combined shift and rotation. In the latter application, these methods were used in a lot of studies as a reference standard. The aim of this study was to analyze, whether common pantographic methods in general are able to distinguish between a pure rotation and a movement with rotational and translational portions. The mathematical proof of this analysis was done with theoretical kinematic considerations and compared with computer simulations. The results show for the first time that there exist combinations of rotational and translational movements of the temporomandibular joint which cannot be separated from pure rotational movements using actual pantographic methods. Even more, the consequence is a shifted location of the (combined) finite center (axis) of rotation in comparison to the true center (axis) of rotation: in case of a translational portion of only 1 mm, this is a displacement of around ±6 mm and, in case of 2 mm translation, a displacement of ±12 mm. This finding necessitates a critical reinterpretation of former studies using pantographic methods as a reference standard. Further, under some circumstances it may also affect the applicability of articulator concepts and the interpretation of functional signs.
Topics: Biomechanical Phenomena; Computer Simulation; Humans; Mandible; Movement; Rotation; Temporomandibular Joint
PubMed: 32116047
DOI: 10.1080/10255842.2020.1724975 -
Journal of Indian Prosthodontic Society 2023The fabrication of an accurate prosthesis depends mainly on precise recording of the maxillo-mandibular relationship of the patient and transferring it to the...
Evaluation of dimensional stability, compressive resistance, and detail reproduction of thermoplastic resin (IMPRESS), elastomeric and composite bite registration material: An study.
AIM
The fabrication of an accurate prosthesis depends mainly on precise recording of the maxillo-mandibular relationship of the patient and transferring it to the articulator. BDIMPRESS is a new thermoplastic material that has been proposed as a potential material to be used as an inter-occlusal registration, but there has been no literature evidence regarding its application as a bite registration. The main purpose of this study is to evaluate and compare the dimensional stability, detail reproduction, and compressive resistance of new interocclusal recording material with other two commonly used materials.
SETTINGS AND DESIGN
In Vitro Comparative study.
MATERIALS AND METHODS
The study was conducted according to ADA Specification standards of testing for dimensional stability, detail reproduction and compressive resistance. Specimens were prepared for three different materials (Thermoplastic resin, Polyvinyl siloxane, and Bis- acrylic) with 12 samples each.
STATISTICAL ANALYSIS USED
One way ANOVA was done for statistical analysis.
RESULTS
Polyvinyl siloxane material was dimensionally stable (mean at 1 hr: 24.928 mm; 24 hrs: 24.919 mm & 48 hrs: 24.912 mm) followed by Bis- acrylic material (mean at 1 hr: 24.851 mm; 24 hrs: 24.825 mm & 48 hrs: 24.815 mm). On one way ANOVA, strong significance was observed between groups (P = 0.00). Thermoplastic resin showed higher amount of detail reproduction with 10 (out of 12 samples) samples showing satisfactory results. While bis- acrylic material showed the least compressive resistance (Strain %: 0.484%; Displacement- 0.0990mm). One-way ANOVA showed presence of significance between the groups (P = 0.024).
CONCLUSION
Polyvinyl siloxane showed superior dimensional stability, thermoplastic resin showed better detail reproduction and bis- acrylic showed high resistance to compression over other materials.
Topics: Humans; Siloxanes; Jaw Relation Record; Polyvinyls; Resins, Plant; Polymethyl Methacrylate
PubMed: 36588377
DOI: 10.4103/jips.jips_146_22 -
Healthcare (Basel, Switzerland) Apr 2022This case report describes a 70 year-old man with IVA lung cancer who required oral function rehabilitation by fabricating dentures with a simplified clinical remount...
This case report describes a 70 year-old man with IVA lung cancer who required oral function rehabilitation by fabricating dentures with a simplified clinical remount technique. A pair of dentures were fabricated for a 70-year-old man with stage IVA lung cancer. Due to severe bimaxillary exostoses, the dentures could not properly extend and achieve a peripheral seal. The treatment philosophy was to stabilize the dentures and achieve proper function with optimized occlusion. The simplified Lauritzen clinical remount technique was performed at the time of denture delivery and 3 months later. After the second clinical remount procedure, the patient was able to eat meals with the dentures and maintained in a stable condition. Compared with the original technique, the simplified Lauritzen clinical remount omits the facebow transfer and keeps the condylar guidance setting and the Bennett angle unchanged during the adjustment. The prostheses are mounted to a type 3, non-arcon type articulator with anterior stop screws attached to the bilateral condylar parts. With the aid of anterior stop screws, the eccentric movement of dentures can be differentiated on a millimeter scale and balanced easily. It is effective to use occlusal-optimized dentures and the clinical remount technique, especially in difficult cases.
PubMed: 35455860
DOI: 10.3390/healthcare10040682 -
Journal of Prosthodontics : Official... Aug 2020The virtual patient, a unique computer simulation of the patient's face, teeth, oral mucosa, and bone, provides an extraordinary mechanism for digital dental implant...
The virtual patient, a unique computer simulation of the patient's face, teeth, oral mucosa, and bone, provides an extraordinary mechanism for digital dental implant surgery planning and prosthetic design. However, the seamless registration of digital scans with functional information in the context of a virtual articulator remains a challenge. This report describes the treatment of a 47-year-old male with full-mouth guided immediate implant placement and immediate loading of CAD/CAM interim prostheses. Utilizing a novel digital workflow, a multifactorial registration of the vertical dimension of occlusion, centric occlusion, and facebow record were completed digitally and paired within a digital articulator. Utilizing this innovative approach, a complex treatment plan and procedure was executed smoothly with a successful prosthetic outcome demonstrating good fit, occlusion, esthetics, and patient reported satisfaction.
Topics: Computer Simulation; Computer-Aided Design; Dental Articulators; Dental Implants; Dental Prosthesis, Implant-Supported; Esthetics, Dental; Humans; Male; Middle Aged
PubMed: 32424940
DOI: 10.1111/jopr.13204 -
Revista Cientifica Odontologica... 2021To compare the angle of the sagittal condylar guidance obtained from the radiographic and clinical records of dentate patients.
OBJECTIVE
To compare the angle of the sagittal condylar guidance obtained from the radiographic and clinical records of dentate patients.
MATERIALS AND METHODS
The sample consisted of 32 patients in whom strict lateral radiography and positional records were performed: in centric relation, protrusive recording 5 mm in right laterality and protrusive recording 5 mm in left laterality. With the positional registration of the facebow, the upper model was articulated, while the lower model was articulated with the positional registration in centric relation, and with the protrusive lateral registrations on the right and left side the condylar guidance was obtained for programming the semi-adjustable articulator. Statistics were performed with the SPSS program version 24 in Spanish. Normality was evaluated using the Shapiro-Wilk test, for data with normal distribution, and the Student's T test and Pearson's correlation were performed in descriptive statistics.
RESULTS
The statistical analyses showed that gender and age influence the angle measurement of the sagittal condylar guide. The radiographic method presented a condylar guide angle of 35.69 ± 5.18, being 35.69 ± 5.16 with the clinical method (p> 0.05). Pearson's correlation test showed an important correlation between the two methods (r = 0.948, p <0.001).
CONCLUSIONS
There is a high correlation in the measurements obtained from the angle of the sagittal condylar guide and the radiographic and clinical records, indicating that both methods are effective.
PubMed: 38465274
DOI: 10.21142/2523-2754-0902-2021-060 -
Case Reports in Dentistry 2021This case report presents a 19-year-old male patient with hypohidrotic ectodermal dysplasia, having a chief complaint of multiple missing teeth. Atraumatic extraction of...
This case report presents a 19-year-old male patient with hypohidrotic ectodermal dysplasia, having a chief complaint of multiple missing teeth. Atraumatic extraction of the teeth with hopeless prognosis was done, and teeth with grade 2 mobility were submerged using cast dowel and coping. Following this, incremental increase in the vertical dimension was made using removable flexible splint of two-millimeter thickness. After facebow transfer and making appropriate eccentric bite records to program the semiadjustable articulator, wax-up was done at the desired vertical dimension (VD). The upper arch was finally restored using a long-span fixed partial denture and lower arch using bilateral attachment (Rhein 83) retained cast removable partial denture as a definitive prosthesis. Therefore, in conditions like hypodontia or oligodontia caused due to ectodermal dysplasia, attachment retained removable partial denture may prove beneficial by effectively distributing the occlusal forces. In clinical scenarios where implant is not feasible or not opted by the patient, this combination treatment may be a viable option.
PubMed: 34931149
DOI: 10.1155/2021/7469595 -
Psychonomic Bulletin & Review Aug 2019The relationship between speech perception and production is central to understanding language processing, yet remains under debate, particularly in early development....
The relationship between speech perception and production is central to understanding language processing, yet remains under debate, particularly in early development. Recent research suggests that in infants aged 6 months, when the native phonological system is still being established, sensorimotor information from the articulators influences speech perception: The placement of a teething toy restricting tongue-tip movements interfered with infants' discrimination of a non-native contrast, /Da/-/da/, that involves tongue-tip movement. This effect was selective: A different teething toy that prevented lip closure but not tongue-tip movement did not disrupt discrimination. We conducted two sets of studies to replicate and extend these findings. Experiments 1 and 2 replicated the study by Bruderer et al. (Proceedings of the National Academy of Sciences of the United States of America, 112 (44), 13531-13536, 2015), but with synthesized auditory stimuli. Infants discriminated the non-native contrast (dental /da/ - retroflex /Da/) (Experiment 1), but showed no evidence of discrimination when the tongue-tip movement was prevented with a teething toy (Experiment 2). Experiments 3 and 4 extended this work to a native phonetic contrast (bilabial /ba/ - dental /da/). Infants discriminated the distinction with no teething toy present (Experiment 3), but when they were given a teething toy that interfered only with lip closure, a movement involved in the production of /ba/, discrimination was disrupted (Experiment 4). Importantly, this was the same teething toy that did not interfere with discrimination of /da/-/Da/ in Bruderer et al. (2015). These findings reveal specificity in the relation between sensorimotor and perceptual processes in pre-babbling infants, and show generalizability to a second phonetic contrast.
Topics: Feedback, Sensory; Female; Humans; Infant; Language Development; Male; Movement; Phonetics; Speech Perception; Tongue
PubMed: 31037603
DOI: 10.3758/s13423-019-01601-0 -
Journal of Pharmacy & Bioallied Sciences Feb 2024The transfer of interocclusal data from the patient's mouth to articulators utilizing various types of recording media is necessary for the production of dental...
UNLABELLED
The transfer of interocclusal data from the patient's mouth to articulators utilizing various types of recording media is necessary for the production of dental prostheses. Occlusal errors in the final prosthesis result from any discrepancies in these interocclusal records.
MATERIALS AND METHODS
The purpose of this study was to assess the linear dimensional changes in the four elastomeric interocclusal recording materials as well as the material's resistance to compression during the cast mounting on the articulator.
RESULT
All four elastomeric materials showed decreasing stability over time and 2 mm thickness showed the highest compression resistance with minimal articulation error.
CONCLUSION
Dimensional stability depends on material and time factors, and compressive resistance decreases with increasing thickness.
PubMed: 38595621
DOI: 10.4103/jpbs.jpbs_1047_23