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The Journal of Contemporary Dental... Jan 2022To systematically evaluate the literature evidence regarding the suitability of the T-scan occlusal system for implant supported prostheses.
AIM
To systematically evaluate the literature evidence regarding the suitability of the T-scan occlusal system for implant supported prostheses.
MATERIALS AND METHODS
A thorough bibliographic search was conducted on PubMed, Google Scholar, Cochrane library, Web of Science, EMBASE, and Scopus to collect relevant articles published from January 1, 2008 to August 30, 2021, using a combination of the following words: "T-scan," "Implant supported prostheses," and "dental implant" according to the PRISMA guidelines for the focused research question constructed using the PICO criteria. Randomized control trials, prospective studies, retrospective studies on the use of T-scan system in implant-supported prostheses reported in English language were included in the study.
RESULTS
This review consisted of 17 studies and 359 patients rehabilitated with 1,126 implants. In 3 studies, removable types of prostheses were given over implants, and in 14 studies, fixed types of prostheses were given. Nine studies determined the percentage of occlusal force magnitude and occlusion time sequence. Three studies measured the localization of the occlusion center. T-scan was used in two studies to measure the amount of gingival crevicular fluid after occlusal adjustment. The follow-up period ranged from 6 months to 2 years or more.
CONCLUSION
T-scan proved with better results than other occlusal analysis indicators in terms of occlusion measurement, clinical execution, quantify the location and contact timing, and occlusion in 3D with more precision.
CLINICAL SIGNIFICANCE
T-scan occlusal analysis system is widely used in dentistry and there is an increase in the number of studies, so a systematic review evaluating and comparing results is warranted.
Topics: Dental Implants; Dental Occlusion; Dental Prosthesis, Implant-Supported; Humans; Prospective Studies; Retrospective Studies
PubMed: 35656667
DOI: No ID Found -
The Journal of Prosthetic Dentistry Feb 2020Complete seating of a single crown may not be possible if the interproximal contacts are excessively tight. Incomplete seating can lead to open margins, inflammation of...
STATEMENT OF PROBLEM
Complete seating of a single crown may not be possible if the interproximal contacts are excessively tight. Incomplete seating can lead to open margins, inflammation of the gingival tissue, and recurrent dental caries.
PURPOSE
The purpose of this in vitro study was to determine the accuracy of 3 different methods of evaluating interproximal contacts when seating a single crown. MATERIAL AND METHODS: Thirty-five restorative dentists practicing in the Lincoln, Nebraska, area were polled to determine the methods they used most commonly to evaluate the interproximal contacts of crowns. These dentists then evaluated the interproximal contacts of 9 anatomic contour zirconia crowns on a dentoform using 3 different methods: floss and explorer, occlusal articulating film (AccuFilm), and shim stock. Crown fit was evaluated using 1 method at a time. Each crown was recorded as either "accept" or "reject" according to the individual clinician. All data were analyzed with the McNemar test (α=.05).
RESULTS
Of the 35 restorative dentists polled, 34 identified floss and explorer, 9 identified occlusal articulating film, 3 identified shim stock, and 3 identified an occlusal spray as their method of evaluating interproximal contacts. These methods were used either alone or in conjunction with other methods. Evaluation of the in vitro data revealed that shim stock and occlusal articulating film were significantly more accurate than floss and explorer for assessing interproximal contacts in poorly fitting crowns (P<.001). For well-fitting crowns, shim stock and occlusal articulating film were significantly more accurate than floss and explorer (P<.001).
CONCLUSIONS
This study showed that the floss and explorer method was the least accurate means of evaluating the interproximal fit of crowns. Shim stock provided the most accurate method of evaluating interproximal contact, and occlusal articulating film provided both high accuracy and a visible mark to facilitate adjustment.
Topics: Crowns; Dental Caries; Humans; Tooth
PubMed: 31227244
DOI: 10.1016/j.prosdent.2018.10.029 -
Journal of Prosthodontics : Official... Feb 2021To assess whether the occlusion of metal-ceramic crowns, as received from the laboratory, and the time taken to adjust the occlusion of crowns not deemed acceptable, can...
PURPOSE
To assess whether the occlusion of metal-ceramic crowns, as received from the laboratory, and the time taken to adjust the occlusion of crowns not deemed acceptable, can be reduced by fabricating the crowns with controlled amounts of infra-occlusion during the laboratory phase.
MATERIAL AND METHODS
An opposing set of typodonts, articulated in maximum intercuspal position served as the patient in an in vitro simulation. Seventy-five metal-ceramic crowns were fabricated for the mandibular right second molar with three different occlusal contact specifications: A, control group had occlusal contacts shared evenly by the crown and the neighboring teeth (n = 25); B, first experimental group had the occlusion relieved until 2 shimstock foils were able to be pulled from between the crown and the opposing tooth without tugging (n = 25); C, second experimental group had the occlusion relieved until 4 shimstock foils were able to be pulled from between the crown and the opposing tooth without tugging (n = 25). The occlusion of each crown, as received from the laboratory, was assessed using one of three categories (Excellent, Acceptable, and Poor). Chi-square analysis was used to test the differences in occlusal outcomes between the three study groups. For all of those rated "Acceptable," the time taken to adjust each crown to proper occlusion was recorded. One-way analysis of variance (ANOVA) and Bonferroni tests were carried out to compare the adjustment times across the three study groups.
RESULTS
The 2-shim group had the best outcome, with 56% of the crowns rated as "Excellent" (p = 0.001). In addition, there were statistically significant differences in adjustment times between the control group (A) and the 2-shim (B) and the 4-shim (C) groups (p = 0.0001), but not between the 2-shim (B) and 4-shim (C) groups (p = 0.08).
CONCLUSIONS
Metal-ceramic crowns fabricated with controlled interocclusal relief of 2- and 4-shims each required less time for chairside occlusal adjustment than crowns fabricated in the laboratory to conventional occlusal contact. However, the overall superior outcome, in terms of the possibility for immediate insertion as received from the laboratory as well as favorable chairside adjustment time, for the 2-shim prespacing suggests that this dimension is the preferred option over 4-shim prespacing to reduce occlusal inaccuracies of indirect restorations.
Topics: Crowns; Dental Occlusion; Dental Porcelain; Dental Prosthesis Design; Humans; Molar; Occlusal Adjustment; Tooth
PubMed: 32881153
DOI: 10.1111/jopr.13252 -
The Journal of Prosthetic Dentistry Feb 2020How occlusal adjustments and finishing of high-translucent monolithic zirconia restorations affect their mechanical behavior is unclear.
STATEMENT OF PROBLEM
How occlusal adjustments and finishing of high-translucent monolithic zirconia restorations affect their mechanical behavior is unclear.
PURPOSE
The purpose of this in vitro study was to investigate the effect of grinding, finishing, and hydrothermal degradation on the roughness, flexural strength, and reliability of fully stabilized zirconia (FSZ) and partially stabilized zirconia (PSZ) for monolithic restorations.
MATERIAL AND METHODS
Specimens of PSZ and FSZ were divided into 5 groups: control (Ctrl); those ground by using coarse diamond rotary instrument (Gr); those that underwent grinding, polishing (diamond rubber), and glazing (GrPolGl); those that underwent grinding and glazing (GrGl); and those that underwent grinding and polishing (GrPol). These groups were subdivided into nonaged and hydrothermally aged in autoclave (134 °C, 200 kPa). Three-point bend tests (flexural strength [FS]) were performed (n=30), and roughness (Ra) was measured by using a contact profilometer (n=30). The Weibull moduli were obtained from the FS data. The intergroup FS was analyzed by the Kruskal-Wallis test and Student-Newman-Keuls method, and the intragroup FS, Mann-Whitney tests (α=.05).
RESULTS
The median FS for PSZ (MPa) for the aforementioned groups is as follows: Gr (1147.8)=GrPol (1210.3)>GrPolGl (815.6)>GrGl (569.7)=Ctrl (583.0). The FS for FSZ (MPa) for the aforementioned groups is as follows: GrPolGl (404.2)=GrGl (427.0)
CONCLUSIONS
Monolithic zirconia exhibited a different mechanical behavior after adjustment procedures and hydrothermal aging. Grinding increased the roughness, and polishing reduced the roughness of the ground surface. FS improvement by finishing depended on the type of zirconia. Glazing smoothened the surface but tended to decrease the FS. Aging of PSZ improved the FS except in the control and glazed groups, whereas FSZ was not affected by aging, except in the GrGl group.
Topics: Dental Polishing; Humans; Materials Testing; Reproducibility of Results; Surface Properties; Zirconium
PubMed: 31079884
DOI: 10.1016/j.prosdent.2018.12.013 -
Computational and Mathematical Methods... 2021Based on deep learning, the characteristics of food impaction with tight proximal contacts were studied to guide the subsequent clinical treatment of occlusal...
OBJECTIVE
Based on deep learning, the characteristics of food impaction with tight proximal contacts were studied to guide the subsequent clinical treatment of occlusal adjustment. At the same time, digital model building, software measurement, and statistical correlation analysis were used to explore the cause of tooth impaction and to provide evidence for clinical treatment.
METHODS
Volunteers with ( = 250) and without ( = 250) tooth impaction were recruited, respectively, to conduct a questionnaire survey. Meanwhile, models were made and perfused by skilled clinical physicians for these patients, and characteristics such as adjacent line length, adjacent surface area, tongue abduction gap angle, buccal abduction gap angle, and occlusal abduction gap angle were measured. A normality test, differential analysis, correlation analysis of pathological characteristics of the impaction group, principal component analysis (PCA), and binary logistic regression analysis were performed.
RESULTS
The adjacent line length, adjacent surface area, tongue abduction gap angle, buccal abduction gap angle, and occlusal abduction gap angle all met normal distribution. There were statistically significant differences in adjacent line length ( < 0.001), adjacent surface area ( < 0.001), and occlusal abduction gap angle ( < 0.001) between the two groups. After dimensionality reduction by PCA on characteristics, adjacent line length, adjacent surface area, buccal abduction gap angle, and occlusal abduction gap angle had a strong correlation with the principal components. Binary logistic regression analysis showed that adjacent line length and adjacent surface area had positive effects on impaction. The buccal abduction gap angle and occlusal abduction gap angle had a significant negative influence on impaction.
CONCLUSION
Adjacent line length, adjacent surface area, buccal abduction gap angle, and occlusal abduction gap angle are independent factors influencing food impaction.
Topics: Adult; Computational Biology; Deep Learning; Dental Occlusion; Food; Humans; Imaging, Three-Dimensional; Mastication; Middle Aged; Models, Dental; Occlusal Adjustment; Tooth Diseases
PubMed: 34777558
DOI: 10.1155/2021/1000820 -
Integrating Facial and Intraoral Scans for Digital Esthetic and Occlusal Design: A Technical Report.Journal of Prosthodontics : Official... Oct 2021The provisional prosthesis is a prerequisite for prosthodontic rehabilitation. The purpose of this technique was to register facial and intraoral scans predictably. A 3D...
The provisional prosthesis is a prerequisite for prosthodontic rehabilitation. The purpose of this technique was to register facial and intraoral scans predictably. A 3D virtual patient was created through facial scans, intraoral scans, digital face-bow transfer, and digital cross-articulation technique. This virtual patient allowed predictable positioning of intraoral scans to a virtual articulator by using digital face-bow transfer. The resulting virtual patient facilitated the design of definitive prostheses following a facially generated treatment planning principle. In addition, the virtual articulator was used to improve occlusal design on the definitive prostheses and reduce the need for intraoral adjustment.
Topics: Computer-Aided Design; Dental Articulators; Esthetics; Face; Humans; Patient Care Planning; Prosthodontics
PubMed: 34109701
DOI: 10.1111/jopr.13397 -
Journal of Dentistry Jun 2024The objective of this study was to analyze the occlusal contact characteristics of the food-impacted teeth using a new digital technique.
OBJECTIVES
The objective of this study was to analyze the occlusal contact characteristics of the food-impacted teeth using a new digital technique.
METHODS
A 3D occlusal analysis method was developed for studying the occlusal contact characteristics of teeth affected by food impaction. In this self-controlled study, food-impacted molars from 20 participants constituted the experimental group. The corresponding healthy teeth on the opposite side served as the control group. Variables such as occlusal force (OF), occlusal contact area (OCA), and the number and distribution of occlusal contact points (OCN) in the mesio-distal directions were measured and compared between the two groups.
RESULTS
There was no statistical significant difference in the values of OF, OCA and OCN between the food-impacted molars and the healthy control molars (P > 0.05). However, paired T-tests indicated significant difference in the proportion of mesial OF, OCA, and OCN in the second molars of the experimental group (0.22, 0.28 and 0.28, respectively) and the control group (0.66, 0.63, and 0.63 respectively) (P < 0.001).
CONCLUSIONS
The abnormal distribution of occlusal contacts in the second molar, primarily characterized by excessive occlusal contact in the distal direction may contribute to the occurrence of food impaction.
CLINICAL SIGNIFICANCE
The present study identified variations in the distribution of occlusal contacts and occlusal component force in food-impacted teeth. These findings can assist dentists in making more targeted occlusal adjustments, or applying other treatment modalities, to effectively address food impaction.
PubMed: 38880468
DOI: 10.1016/j.jdent.2024.105133 -
Journal of Prosthodontics : Official... Mar 2024This is a clinical study to compare immediate and staged impression methods in a complete digital workflow for single-unit implants in the posterior area.
PURPOSE
This is a clinical study to compare immediate and staged impression methods in a complete digital workflow for single-unit implants in the posterior area.
MATERIALS AND METHODS
Sixty patients requiring single-unit implant crowns were enrolled. Forty patients were assigned to the test group, immediate digital impression after implant surgery with crown delivery 4 months later. The remaining 20 patients were assigned to the control group, staged digital impressions 4 months after implant surgery, and crown delivery 1 month later. Both workflows involved free-model CAD-CAM crown fabrications. The crowns were scanned before and after clinical adjustment using an intraoral scanner (TRIOS Color; 3Shape). Two 3D digital models were trimmed and superimposed to evaluate the dimensional changes using Geomagic Control software. Chairside times for the entire workflow were recorded. Kruskal-Wallis was performed to compare crown adjustments between two groups, while One-way ANOVA was used to compare chairside time durations between the test and control groups.
RESULTS
All crowns were delivered without refabrication. The average maximum occlusion adjustment of crowns was -353.2 ± 207.1 μm in the test group and -212.7 ± 150.5 μm in the control group (p = 0.02). The average area of occlusal adjustment, measured as an area of deviation larger than 100 μm, was 14.8 ± 15.3 and 8.4 ± 8.1 mm in the test and control groups, respectively (p = 0.056). There were no significant differences in the mesial and distal contact adjustment amounts, or the maximum deviations of the proximal area, between the two groups. The mean chair-side time was 50.25 ± 13.48 and 51.20 ± 5.34 min in the test and control groups, respectively (p = 0.763).
CONCLUSIONS
The immediate impression method in the digital workflow for single-unit implants required more occlusal adjustments of crowns but showed similar chairside times compared to the staged impression method.
PubMed: 38526488
DOI: 10.1111/jopr.13851 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Jun 2023This study aimed to compare the effects of virtual adjustment on occlusal interferences in mandibular posterior single crown and three-unit bridge restorations by using... (Comparative Study)
Comparative Study
OBJECTIVES
This study aimed to compare the effects of virtual adjustment on occlusal interferences in mandibular posterior single crown and three-unit bridge restorations by using the mandibular movement track and the movement parameters of a virtual articulator.
METHODS
Twenty-two participants were recruited. Digital casts of the maxillary and mandibular arches were obtained using an intraoral scanner, and the jaw registration system was used to record the data of the mandibular movement track and the movement parameters of the articulator. Four kinds of restorations with 0.3 mm occlusal interferences were designed with dental design software. In particular, single crowns were designed for teeth 44 and 46, whereas three-unit bridges were designed for teeth 44-46 and 45-47, and the corresponding natural teeth were virtually extracted. Virtual adjustment of the restorations was performed using two dynamic occlusal recordings, namely, the mandibular movement track and the movement parameters of the virtual articulator. A reverse-engineering software was used to measure the root-mean-square of the three-dimensional deviation of the occlusal surfaces between natural teeth and the adjusted restorations. The differences between the two methods of virtual-occlusion adjustment were compared and analyzed.
RESULTS
For the same group of restorations, the three-dimensional deviation of the mandibular movement track group were lower than those of the virtual articulator group, and the differences were statistically significant (<0.05). For the four groups of restorations adjusted by the same method, the three-dimensional deviation of the 46-tooth single crown was the largest and the smallest three-dimensional deviation was that of the 44-tooth single crown. Statistical differences existed between the 44-tooth single crown and the other groups (<0.05).
CONCLUSIONS
For the occlusal design of posterior single crown and three-unit bridge, the mandibular movement track could be a more effective approach to virtual occlusal adjustment than the movement parameters of the virtual articulator.
Topics: Humans; Mouth, Edentulous; Occlusal Adjustment; Jaw Relation Record; Dental Articulators; Software
PubMed: 37277790
DOI: 10.7518/hxkq.2023.2022452 -
British Dental Journal Jul 2021The occlusal matrix technique appears as an alternative to the conventional restorative technique. The aim of this study is to present treatment options for the decayed...
The occlusal matrix technique appears as an alternative to the conventional restorative technique. The aim of this study is to present treatment options for the decayed occlusal surface of posterior teeth by means of an occlusal matrix made with different materials, for an accurate reproduction of the tooth surface. This paper presents five clinical cases using five different materials, such as Bite-Perf, flowable composite, self-curing acrylic resin, silicone and thermoforming foil. Before light-curing, the last layer of composite resin, the matrix, is repositioned and firmly pressed so the replication of the original occlusal anatomy can be achieved. When using an occlusal matrix, minimal or no finishing and polishing procedures are needed and the offered aesthetics are clearly an advantage. Moreover, this technique makes up for the additional chairside work time. The occlusal matrix technique is demonstrated to be effective for direct composite resin restorations in posterior teeth, allowing a reliable and predictable reproduction of the occlusal anatomy and clinical adjustment. For this purpose, a clear material is preferable since it allows light transmission.
Topics: Acrylic Resins; Composite Resins; Dental Restoration, Permanent; Esthetics, Dental; Molar
PubMed: 34302088
DOI: 10.1038/s41415-021-3225-3