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BDJ Open May 2023To measure the required clinical time and volume of occlusal adjustment when the maxillary cast is positioned in a virtual articulator using one of three methods:...
OBJECTIVE
To measure the required clinical time and volume of occlusal adjustment when the maxillary cast is positioned in a virtual articulator using one of three methods: digitization of a facebow-mounted mechanical articulator (group A), virtual Bonwill triangle (group B) or a 3D face scan (group F).
MATERIALS AND METHODS
In this randomized, triple-blind, crossover trial; 11 participants were enrolled. Every participant had one molar indicated for a single crown restoration. Three crowns were designed and milled for every participant molar totaling 33 crowns. Each of the three crowns was fabricated with the participant's casts virtually mounted utilizing a different method. An impression was taken of the crown in place before occlusal adjustment. The occlusal adjustment was then performed and timed with the three crowns in the different groups. After the occlusal adjustment, an impression of the adjusted crown was taken. The pre-adjustment and post-adjustment impressions were digitally superimposed and the volume difference was measured. The Kruskal-Wallis test was used to compare the groups.
RESULTS
Group A showed the shortest mean adjustment time (3:44.59 ± 3:39.07) followed by group F (4:30.09 ± 2:01.50) and group B (4:35.30 ± 2:32.33). The mean adjustment volume for group A was (28 ± 19.1 mm) followed by group F (30.5 ± 18.8 mm) and group B (40.6 ± 29.5 mm). Different virtual mounting methods had no statistically significant effect on adjustment time (P-value = 0.538) or adjustment volume (P-value = 0.490).
CONCLUSIONS
A simplified approach in virtual articulator mounting appears to be justified in the construction of a single full-coverage prosthesis. Added labor, time and cost of more elaborate virtual mounting methods seem to be counterproductive.
PubMed: 37164989
DOI: 10.1038/s41405-023-00146-8 -
Journal of Esthetic and Restorative... Jul 2023To describe a technique for fabricating an additively manufactured maxillary occlusal device using a complete digital workflow.
OBJECTIVE
To describe a technique for fabricating an additively manufactured maxillary occlusal device using a complete digital workflow.
CLINICAL CONSIDERATIONS
The maxillary occlusal device design may include an anterior platform to guide the positioning of the mandible in a reproducible position for facilitating the delivery procedure.
CONCLUSIONS
The described technique provides a more efficient and less time-consuming method for designing and manufacturing a printed occlusal device, when compared with conventional fabrication techniques.
CLINICAL SIGNIFICANCE
The additively manufactured occlusal device designed with an anterior platform guides the positioning of the mandible in a reproducible position, facilitates the delivery procedures, and produces a more efficient and less time-consuming method when compared with conventional methods.
Topics: Occlusal Adjustment; Mandible; Maxilla; Workflow
PubMed: 37162127
DOI: 10.1111/jerd.13061 -
Journal of Prosthodontics : Official... Jan 2024Clinically, the proximal surfaces of teeth adjacent to an implant restoration usually need to be adjusted to build a preferable adjacency relationship. However, it is...
Clinically, the proximal surfaces of teeth adjacent to an implant restoration usually need to be adjusted to build a preferable adjacency relationship. However, it is difficult for freehand preparation to get a favorable proximal contour in some cases. In the workflow presented here, virtual grinding can be made to adjacent teeth, under the consideration of functional reconstruction and biological requirements, and then the grinding can be implemented using digital templates and a specialized bur. This allows for more precise and accurate adjustments to be made during the clinical procedure, reducing the risk of over- or under-preparation of the proximal surfaces. In addition, the use of specialized diamond burs and grinding guides can make the procedure more efficient and streamlined, reducing the time required for proximal adjustment and minimizing patient discomfort. The resulting implant-supported prosthesis is more likely to function properly and last longer, as the precise proximal contacts can help distribute occlusal forces more evenly across the dentition. Overall, the use of digital technology for precise adjustment of proximal contacts during implant restorations represents an important advancement in modern dentistry, enabling dentists to provide their patients with more accurate, efficient, and effective dental care.
Topics: Humans; Dental Implants; Workflow; Dental Prosthesis, Implant-Supported; Computers; Diamond; Computer-Aided Design
PubMed: 37157952
DOI: 10.1111/jopr.13701 -
Shanghai Kou Qiang Yi Xue = Shanghai... Apr 2023To compare the effects of three occlusal adjustment methods in different sequences by articulating paper on the delayed occlusal characteristics of single molars.
PURPOSE
To compare the effects of three occlusal adjustment methods in different sequences by articulating paper on the delayed occlusal characteristics of single molars.
METHODS
Thirty-two implants of first molars were divided into group A(n=12), group B (n=12) and group C (n=12) by sequential adjustment according to random number means, and (100+40), (100+50+30) and (100+40+20) μm sequence occlusal papers were used for occlusal adjustment, respectively. TeeTester was used to measure the delay time and force ratio between prosthesis and adjacent teeth at restoration day, 3 and 6 months after restoration, and to record the number of cases readjusting in each group during follow-up. SPSS 25.0 software package was used for data analysis.
RESULTS
There were significant differences in delay time between groups at restoration day (P<0.05), and 3 and 6 months after restoration, delay time of group C was still smaller than that of group A and B (P<0.05). During follow-up, the time of each group showed a trend of shortening (P<0.05), but there was still delayed occlusion. Compared with group B and C, the force ratio in group A was lower at each time(P<0.05). The ratio of each group showed an increasing trend during follow-up (P<0.05), and group C showed the largest increase (P<0.001). The number of cases readjusting was relatively small in group A, and the most was in group C(P<0.05). There was positive correlation between delay time and force difference of prosthesis and adjacent teeth(P<0.001).
CONCLUSIONS
The (100+40) μm sequence group had higher occlusal stability and better clinical applicability. The smaller the occlusal contact space realized by the sequential method, the greater the change might be, which requires close follow-up in clinical practice.
Topics: Occlusal Adjustment; Bite Force; Tooth; Molar; Dental Occlusion
PubMed: 37154006
DOI: No ID Found -
Computer Methods in Biomechanics and... 2024This study aims to investigate the morphological characteristics of the temporomandibular joint (TMJ) in the patients with anterior disc displacement with reduction...
This study aims to investigate the morphological characteristics of the temporomandibular joint (TMJ) in the patients with anterior disc displacement with reduction (ADDwR) and the alterations after occlusal splint treatment. Thirty ADDwR patients and ten asymptomatic subjects were recruited. Thirteen parameters were adopted, along with automatic computation and presentation of the joint space to characterize the TMJ morphologies. Statistical results showed that morphological discrepancies between the patients and the asymptomatic subjects were ubiquitous. The adjustment of condyle position through occlusal splint treatment can result in joint spaces widening and has positive effects on mitigating the conditions of ADDwR.
Topics: Humans; Temporomandibular Joint Disc; Temporomandibular Joint Disorders; Magnetic Resonance Imaging; Joint Dislocations; Temporomandibular Joint
PubMed: 36988303
DOI: 10.1080/10255842.2023.2188990 -
Journal of Sleep Research Aug 2023Masticatory muscle activity during sleep has been considered independent of variations in the structural characteristics of the dental occlusion. However, scientific... (Randomized Controlled Trial)
Randomized Controlled Trial
Masticatory muscle activity during sleep has been considered independent of variations in the structural characteristics of the dental occlusion. However, scientific evidence contradicting an occlusal causal role is missing. The purpose of this study was to test the null hypothesis that sleep bruxism (SB) is independent of the presence of occlusal interferences. A total of 17 healthy female subjects (mean [SD] age 24.9 [4.1] years) presenting with SB, and randomly divided into two groups, were evaluated after receiving either elimination of occlusal interferences (Test group) or elimination of sharp margins without change in occlusal contacts (Control group). Audio-video polysomnography (PSG) recordings were undertaken before and after treatment (mean [SD] duration 14.4 [3.8] months). Two subjects in each group (< 2 rhythmic masticatory muscle activity [RMMA]/h) were excluded for statistical analysis. During the total sleep time (TST), the Test group exhibited a higher reduction in frequency of episodes per hour than the Control group (p < 0.05). The reduction in duration of episodes was also higher in the Test group during the TST. The Test group presented an increase in sleep stage N3 (p < 0.05) at the final PSG when compared with the initial PSG, and a higher percentage of N3 (p < 0.05) at the final PSG when compared to the Control group. Elimination of occlusal interferences resulted in a significant reduction of masseter and temporal muscle activity during sleep in females presenting with SB. Based on these results, the null hypothesis is rejected. The hypothesis of occlusal interferences as a risk factor for SB is still patent.
Topics: Humans; Female; Young Adult; Adult; Sleep Bruxism; Occlusal Adjustment; Electromyography; Masticatory Muscles; Masseter Muscle
PubMed: 36918352
DOI: 10.1111/jsr.13879 -
The Cleft Palate-craniofacial Journal :... Jul 2024To evaluate the influence of filling material and timing of surgery on radiograph outcomes of alveolar grafting with premaxillary osteotomy. The null hypothesis was that...
OBJECTIVE
To evaluate the influence of filling material and timing of surgery on radiograph outcomes of alveolar grafting with premaxillary osteotomy. The null hypothesis was that radiographic outcomes would be similar with both rhBMP-2 (rhBMP-2G) and cancellous bone from the iliac crest (IG), regardless of the timing of surgery.
DESIGN
Cross-sectional study with consecutive sampling of 56 periapical or occlusal radiographs taken 12 months after surgery.
SETTING
A single tertiary craniofacial center.
PATIENTS/PARTICIPANTS
Twenty-eight patients with complete bilateral cleft lip and palate and mean age of 13 years. The individuals underwent bilateral alveolar grafting associated with premaxillary osteotomy (AG + PO) with rhBMP-2 or cancellous bone from the iliac crest.
INTERVENTIONS
Experienced maxillofacial surgeons used the same surgical technique in both groups. AG + PO were assigned as success or failure by 3 blinded raters based on modified Bergland and SWAG scales.
MAIN OUTCOME MEASURES
The influence of filling materials and timing of surgery on radiographic outcomes was verified by Fisher's exact test and chi-square test ( < .05).
RESULTS
There was no significance variation between the mean age of participants in the rhBMP-2G and IG ( = .471). Scales showed almost perfect reliability (agreement rate = 96.4%; K = 0.85). rhBMP-2G and IG had similar success rates with modified Bergland scale (85.7% and 82.1%) and SWAG scale (92.9% and 82.1%), respectively. However, only modified Bergland scale found influence of age on radiographic outcomes ( = .025).
CONCLUSIONS
AG + PO performed with rhBMP-2 and iliac crest bone showed similar radiographic success rates, regardless of the timing of surgery.
Topics: Adolescent; Female; Humans; Male; Alveolar Bone Grafting; Bone Morphogenetic Protein 2; Bone Transplantation; Cleft Lip; Cleft Palate; Cross-Sectional Studies; Ilium; Osteotomy; Recombinant Proteins; Transforming Growth Factor beta; Treatment Outcome
PubMed: 36843505
DOI: 10.1177/10556656231160396 -
Journal of Clinical Medicine Jan 2023The purpose of this retrospective study was to evaluate computer-assisted virtual surgery and the outcomes of mandibular reconstruction using an autogenous particulate...
Towards Optimum Mandibular Reconstruction for Dental Occlusal Rehabilitation: From Preoperative Virtual Surgery to Autogenous Particulate Cancellous Bone and Marrow Graft with Custom-Made Titanium Mesh-A Retrospective Study.
The purpose of this retrospective study was to evaluate computer-assisted virtual surgery and the outcomes of mandibular reconstruction using an autogenous particulate cancellous bone and marrow (PCBM) graft combined with a custom-made titanium mesh (TiMesh) using a three-dimensional (3D) printing model. Eighteen consecutive patients were included, and preoperative virtual simulation surgery was performed using digital data. Segmental bone defects showed deviation of the mandible due to displacement of the condyle and segments, unnatural length of the mandibular body, or poorer intermaxillary relationship compared to the marginal bone defect caused by previous operations. These mandibular disharmonies could be simulated, and virtual surgery was performed on a computer with adjustment of displaced mandibular segments, length of the mandibular body, and dental arch with digital bone augmentation. TiMesh was manually pre-bent using a 3D printing model, and PCBM from the iliac crest was grafted with TiMesh. The short-term clinical results were good; reconstruction of the alveolar crest was prosthetically desirable; and minor complications were observed. In conclusion, virtual reconstruction is crucial for treating complex deviated mandibles. Accurate condylar and dental arch positions with an optimum mandibular length are important for prosthetically satisfactory mandibular reconstruction.
PubMed: 36769770
DOI: 10.3390/jcm12031122 -
Journal of Clinical Medicine Jan 2023The inaccurate maxillomandibular relationship of virtual casts following alignment by the vestibular scan may result in intersection (intermesh penetration) between...
BACKGROUND
The inaccurate maxillomandibular relationship of virtual casts following alignment by the vestibular scan may result in intersection (intermesh penetration) between opposing dental arch surfaces. Intersection occurs at short interocclusal distances in the occlusal contact area (OCA) and may result in infra-occluded definitive restorations. The purpose of this clinical study was to compare initial (by the proprietary scanner software) and new alignments (by a standalone 3D software) of virtual casts regarding OCA and intersection failure. New alignments aimed to rectify intersections by refinement of occlusal contacts.
MATERIAL AND METHODS
The virtual casts of 30 patients following digital and conventional impression-taking were analyzed, which were acquired for single implant restoration in the posterior site. Digital impressions were performed by both IOS 1 (3M True Definition) and IOS 2 (TRIOS 3), either as complete- or partial-arch scans, respectively. Mounted gypsum casts were digitized as complete-arch by a laboratory scanner (LS) in enabled and disabled mode to avoid intersection [LS (+)/LS (-)]. All virtual casts were newly aligned by a 3D software. The difference of the OCA and the area of intersection were calculated for initial and new alignments, using interocclusal distance ranges of 0-100 μm, 0-10 μm or <0 μm (=intersection). The difference of the OCA was compared using a linear mixed model. The distribution of occlusal contact points per modality and alignment was assessed independently by three observers and estimated by inter- and intraclass correlation (ICC) coefficients.
RESULTS
Virtual casts following initial alignment demonstrated intersections irrespective of the modality. The mean area of the intersection was most for IOS 2 (79.23 mm), followed by IOS 1 (48.28 mm), LS (-) (2.77 mm), and LS (+) (2.01 mm) in partial-arch scans. Complete-arch scans demonstrated an area of intersection of 70.63 mm for IOS 1 followed by 65.52 mm (IOS 2), 6.13 mm [LS (-)] and 2.76 mm [LS (+)]. Newly aligned scans showed no intersections. The overall distribution of occlusal contact points demonstrated moderate reliability (ICC 0.63). Good reliability could be observed (ICC 0.9) for LS (-) scans.
CONCLUSIONS
Intersections in the area of occlusal contact points are a phenomenon restricted to virtual casts, which should be considered in CAD/CAM. Initial alignments of LS are less affected by this virtual phenomenon, and contact points may be more distinct according to their anatomic region compared to IOS. Furthermore, intersections can be rectified in a 3D software by adjustment of the maxillomandibular relationship.
PubMed: 36769645
DOI: 10.3390/jcm12030996 -
Clinical Oral Implants Research Mar 2023To investigate the effect of a novel interocclusal recording method on the occlusal accuracy of implant-supported fixed prostheses for partially dentate patients with... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
To investigate the effect of a novel interocclusal recording method on the occlusal accuracy of implant-supported fixed prostheses for partially dentate patients with distal extension.
MATERIALS AND METHODS
Twenty patients with two or more adjacent teeth missing in the distal extension and scheduled to receive implant-supported fixed prostheses were enrolled. Two interocclusal recording methods were used: placing polyvinyl siloxane (PVS) on the interocclusal recording caps (test), and placing PVS on healing abutments (control). The intraoral occlusal contacts in maximal intercuspal position (MIP) were compared with those in the mounted casts to calculate sensitivity and positive predictive value (PPV). Then, patients were randomly allocated into two groups to determine which interocclusal record would be used. The implant prostheses' evaluations mainly included occlusal adjustment height, volume, and time, occlusal contact score based on articulating paper examination. Paired-samples t-test, Mann-Whitney U test, and least squares regression analyzed the statistic differences.
RESULTS
The test method had higher sensitivity to detect intraoral occlusal contacts than the control method (p = .002), but similar PPV (p = .10). During the prostheses' evaluations, the occlusal adjustment height in the test group was significantly lower than that in the control group [99.4 (53.2, 134.2) vs. 159.0 (82.3, 247.8) μm, p = .03], while the occlusal contact score before adjustment was higher (p = .006). The groups had similar occlusal adjustment volume and time.
CONCLUSIONS
The novel interocclusal recording method for implant-supported fixed prostheses was more accurate and could reduce the occlusal adjustment.
Topics: Humans; Dental Implants; Dental Prosthesis, Implant-Supported
PubMed: 36695644
DOI: 10.1111/clr.14040