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Heliyon Jan 2024Different CAD software programs used for designing crowns show variations in marginal and internal fit. Marginal and internal discrepancies may cause poorly fitting...
STATEMENT OF THE PROBLEM
Different CAD software programs used for designing crowns show variations in marginal and internal fit. Marginal and internal discrepancies may cause poorly fitting crowns.
PURPOSE
The aim of this study was to compare the marginal and internal fit of single crown temporary restorations designed using three different CAD software programs.
MATERIALS AND METHODS
Dentbird, Exocad and Inlab 20 were used to design temporary single crowns using the same cement gap. Three experimental groups (n = 10/group) were formed based on the CAD software used. Geomagic Control X three-dimensional analysis software was used to compare the marginal and internal fit among the groups. Measurements were obtained at nine different thickness points. IBM SPSS Statistics, version 22 was used for all statistical analyses.
RESULTS
Among the CAD software programs tested, Dentbird produced the best internal fit on the buccal surface and the best marginal fit on both buccal and mesial surfaces. Exocad achieved the best values on the distal surface for both internal and marginal fit, while Inlab showed the best values on the mesial surface for internal fit and on the palatal surface for marginal fit.
CONCLUSIONS
The Dentbird CAD software program provided the most accurate fit values that closely matched the design. The marginal and internal fit oftemporary crowns may vary depending on the CAD software used.
PubMed: 38293389
DOI: 10.1016/j.heliyon.2024.e24205 -
Journal of Oral Biosciences Mar 2024The current study used a three-dimensional (3D) surface homologous modeling to analyze the structure of maxillary first premolar (P) and second premolar (P) crowns, to...
OBJECTIVES
The current study used a three-dimensional (3D) surface homologous modeling to analyze the structure of maxillary first premolar (P) and second premolar (P) crowns, to identify any morphological differences between them, particularly in their cuspal structures.
METHODS
The study sample comprised 27 male elementary and junior high school students from Chiba Prefecture, Japan. Plaster casts were collected and the 3D coordinates were used to measure the crown structures. Thereafter, principal component (PC) analysis was carried out using the 3D coordinates of the homologous models, containing 4498 anatomical data points, including 9 landmarks.
RESULTS
The findings indicated that P was significantly larger than P, despite both teeth exhibiting similar intercuspal distances. The homologous model analysis revealed that 61.5 % of the total variance could be explained up to the fourth PC. Overall size and shape in the mesiodistal and buccolingual directions were estimated using PC1 and PC2, respectively. Both components highlighted a shape factor, indicating that the buccal cusp was more well-developed than the lingual cusp in P compared to P.
CONCLUSIONS
The variations in the size of the mesial and distal premolar teeth and the relationships between the cusps in the completed tooth crowns can be explained using molecular biology developmental models.
Topics: Humans; Male; Bicuspid; Crowns; Tooth Crown; Molecular Biology; Japan
PubMed: 38280717
DOI: 10.1016/j.job.2024.01.010 -
Archives of Oral Biology Apr 2024This study examines whether larger enamel prism diameters accommodate a greater enamel volume from the enamel-dentine junction (EDJ) to the outer-enamel surface (OES) in...
OBJECTIVE
This study examines whether larger enamel prism diameters accommodate a greater enamel volume from the enamel-dentine junction (EDJ) to the outer-enamel surface (OES) in primate molars, and how prism size relates to enamel thickness and crown location.
DESIGN
We assessed variation in enamel prism diameter in relation to crown location and enamel thickness in catarrhine lower molars (n = 14 species) and one platyrrhine. Prism diameter and enamel thickness were recorded in four locations (lingual lateral; lingual cuspal; buccal cuspal; buccal lateral), using a buccal-lingual section through the centre of the mesial cusps. Ten prism diameter readings were collected at inner (near the EDJ), outer (near the OES) and middle (between the two locations) enamel for each location.
RESULTS
Mean prism diameter values for each species were similar (range: 4.06 µm to 5.81 µm). Prism diameter enlarged from inner to outer enamel, suggesting larger prisms help accommodate the increase in enamel volume from the EDJ to the OES. Average prism diameter does not associate with enamel thickness. Instead, cuspal positions had significantly smaller prism diameter at the EDJ than lateral positions, and larger prism sizes at the OES, leading to an overall similar prism diameter mean for all positions (Lingual lateral: 5.11 µm; Lingual cuspal: 5.04 µm; Buccal cuspal: 4.78 µm; Buccal lateral: 4.99 µm).
CONCLUSIONS
Our study revealed consistent average enamel prism diameters in various crown locations of lower primate molars, potentially contributing to the mechanical integrity and functional optimization of enamel in primates.
Topics: Animals; Hominidae; Dentin; Dental Enamel; Primates; Molar
PubMed: 38266424
DOI: 10.1016/j.archoralbio.2024.105895 -
Journal of Esthetic and Restorative... Jun 2024This study aimed to evaluate the accuracy of an intraoral scanner with near-infrared imaging (NIRI) feature in the diagnosis of interproximal caries and to compare it...
OBJECTIVE
This study aimed to evaluate the accuracy of an intraoral scanner with near-infrared imaging (NIRI) feature in the diagnosis of interproximal caries and to compare it with the visual-tactile method (VTM), bitewing radiography (BWR), and panoramic radiography (PR).
MATERIALS AND METHODS
Six hundred thirty-nine interproximal surfaces (mesial-distal) of posterior teeth from 22 volunteers were examined. Results were scored by VTM, BWR, PR, and NIRI. Lesions were scored as 0 for no-caries, 1 for early-enamel lesion (EEL), and 2 for lesions involving dentino-enamel junction (DEJ). McNemar, Kappa, and Fleis Kappa tests were used to evaluate the agreement levels. Pearson's Chi-square test was used to determine the matching rates after validation.
RESULTS
A good level of agreement was observed between examination methods (Ƙ = 0.613; p < 0.001). In pairwise comparisons, a moderate agreement was seen between all the methods for lesions with DEJ involvement, while a statistically good agreement was observed between BWR and NIRI (Ƙ = 0.675; p < 0.001). As a result of validation, the accuracy of NIRI for molars was considered 85.2% and 75.7% for premolars in EELs, 85.2% for molars, and 70% for premolars regarding the lesions involving DEJ.
CONCLUSIONS
Intraoral scanners with the NIRI feature may be used for diagnosing interproximal caries, especially for permanent molars.
CLINICAL SIGNIFICANCE
Early detection of proximal caries is one of the most essential topics forming the basis of preventive dentistry. This study investigates a caries diagnostic tool integrated into intraoral scanners to diagnose interproximal caries. A caries diagnostic tool integrated into an intraoral scanner may prevent the harmful effects of ionizing radiation in early caries diagnosis and may improve the patient's oral health status.
Topics: Humans; Dental Caries; Adult; Female; Male; Radiography, Panoramic
PubMed: 38263949
DOI: 10.1111/jerd.13198 -
The Journal of Clinical Pediatric... Jan 2024Fixed space maintainers (FSMs) are commonly utilized in pediatric dentistry to prevent space loss following premature tooth extraction. Although previous studies have...
Fixed space maintainers (FSMs) are commonly utilized in pediatric dentistry to prevent space loss following premature tooth extraction. Although previous studies have examined the survival rates and causes of FSM failure, the impact of arm design on failure has not been investigated. This study aimed to investigate the tensile and compressive stresses related to FSMs with different arm designs and evaluate the effect of arm designs on FSM failure. Cone beam computed tomography images of a child who experienced premature loss of a primary mandibular left second molar tooth were retrieved from our database, then processed and simulated using the Rhinoceros software. Finite element analysis was performed to evaluate the stresses on four distinct FSM arm designs under simulated chewing forces. The results showed that the straight-arm FSM design exhibited the highest von Mises principal stress, while FSMs with curved arms and surrounding primary mandibular left first molar in the mesial area demonstrated the lowest von Mises stress accumulation. Intense stress accumulation on the distal surface of tooth 74 was observed in the test models due to the transmitted forces by the FSM. The maximum principal stresses accumulated at the base of the alveolar socket of the mesial root of tooth 36, while the minimum principal stresses were identified at the mesio-marginal area of the alveolar crest. The arm design played a crucial role in enabling the appliance to effectively withstand the stresses accumulating on the Space maintainer (SM) and orthodontic band. Bending the SM arms to match the surrounding profile with curvature increased the stress absorption capacity by increasing the arm length.
Topics: Child; Humans; Finite Element Analysis; Molar; Periodontal Ligament; Stress, Mechanical; Tooth Extraction; Space Maintenance, Orthodontic; Equipment Design
PubMed: 38239170
DOI: 10.22514/jocpd.2024.019 -
European Journal of Dentistry Jan 2024Sterilization eliminates microbial viability by decreasing the biological load, but likewise have the ability to deteriorate the mechanical properties of an implant...
OBJECTIVES
Sterilization eliminates microbial viability by decreasing the biological load, but likewise have the ability to deteriorate the mechanical properties of an implant material. This study intended to evaluate the effect of repeated moist heat sterilization on implant-abutment interface using two different implant systems.
MATERIALS AND METHODS
Forty screw-retained titanium implant-abutment combinations (fixture 3.5 ×10 mm, abutment 2 mm diameter), twenty each from Genesis (Aktiv Implant Systems, United States) and Bredent (SKY, Germany), were divided into four different groups ( = 10) and placed in a computer-aided diagnostic model. The abutments from each group were exposed to first and second autoclave cycle (121°C for 30 minutes), connected back to the fixture and analyzed under scanning electron microscope for marginal gap and surface roughness.
RESULTS
Genesis group showed higher marginal gaps on both sides (buccal/mesial [2.8 ± 0.47]; lingual/distal [2.8 ± 0.33]), while Bredent implant-abutment system (IAS) did not show any changes in marginal gaps after autoclaving. Differences within and between the group were found to be statistically significant. Surface roughness for Genesis (243.7 ± 70.30) and Bredent groups (528.9 ± 213.19) was highest at second autoclave, with Bredent implant-abutment showing higher values for surface roughness than Genesis IAS.
CONCLUSION
Marginal vertical gap increased with autoclaving for Genesis IAS, while Bredent implant abutments were more stable. Surface roughness increases with autoclaving for both Genesis and Bredent group of IAS.
PubMed: 38198814
DOI: 10.1055/s-0043-1776314 -
Journal of Prosthodontic Research Jan 2024To describe a novel digital design technique for creating an individualized emergence profile for implant restoration based on the contralateral tooth.
PURPOSE
To describe a novel digital design technique for creating an individualized emergence profile for implant restoration based on the contralateral tooth.
METHODS
Cone beam computed tomography (CBCT) data were used to accurately obtain a three-dimensional (3D) model of the contralateral tooth, which was mirror-flipped to design the emergence profile. The emergence profile was further divided into critical and subcritical areas; the critical area precisely replicated the mirror-flipped 3D model, whereas the subcritical area featured a slight concavity on the buccal side, flatness on the lingual side, and slight convexity on the mesial and distal surfaces. Subsequently, a milling machine was used to fabricate healing abutments with individualized emergence profiles. The design of the definitive restoration completely duplicated the emergence profile of the individualized healing abutment and was fabricated using a milling machine.
CONCLUSIONS
This technical procedure presents an alternative novel method for designing the emergence profiles of implant restorations, with the potential to improve esthetics and functions as well as to maintain the long-term stability of peri-implant soft and hard tissues.
PubMed: 38171768
DOI: 10.2186/jpr.JPR_D_23_00127 -
PloS One 2023Fractal dimension (FD) analysis has been proposed and validated in osseointegration-related research. The aim of this study was to evaluate the feasibility of FD...
BACKGROUND
Fractal dimension (FD) analysis has been proposed and validated in osseointegration-related research. The aim of this study was to evaluate the feasibility of FD analysis in the osteogenesis detection of bone substitute materials (BSMs) of Bio-Oss in maxillary lateral sinus augmentation.
METHODS
Patients who received lateral maxillary sinus augmentation and underwent grafting with BSMs (Bio-Oss) were included in the study. The cross sections of the BSMs under cone-beam computed tomography (CBCT) at mesial, distal, and sagittal directions were obtained immediately after the graft (T0) and 6 months later (T1), and the obtained images were cropped to include only the BSMs. The FD analysis was performed, and the FD value was obtained by the method of box-counting. Paired t-tests and analysis of variance (ANOVA) were used, and p-values <0.05 was considered statistically significant.
RESULTS
Twelve participants with 22 implants, which were inserted simultaneously after sinus augmentation, were included in this study. A total of 22 mesial, 22 distal, and 14 sagittal images were obtained after FD analysis. The mean FD value and standard deviation at T0 was 1.2860 ± 0.0896, while at T1, it was 1.2508±0.1023; thus, significant differences were detected (p = 0.022). However, the increasing or decreasing trend of FD value was not stable, and no significant difference was detected for FD values of mesial, distal, and sagittal images between T0 and T1. ANOVA indicated that no significant difference was detected among the FD values of mesial, distal, and sagittal images at any timepoint. Differences in FD values between the sexes were not significant either.
CONCLUSIONS
Since the FD analysis for the osteogenesis detection of BSMs in maxillary sinus augmentation indicated unstable trends of change, its feasibility is not reliable. The initially rough surface, self-degradation, and volume change of the BSMs during osteogenesis may be the reason for the variation in FD values.
Topics: Humans; Bone Substitutes; Osteogenesis; Pilot Projects; Sinus Floor Augmentation; Fractals; Transverse Sinuses; Minerals; Bone Transplantation; Maxillary Sinus
PubMed: 38157335
DOI: 10.1371/journal.pone.0296248 -
Zhongguo Xiu Fu Chong Jian Wai Ke Za... Dec 2023To investigate the effect of human subcutaneous adipose-derived stem cells (hADSCs) local transplantation on orthodontically induced root resorption (OIRR) and provide...
OBJECTIVE
To investigate the effect of human subcutaneous adipose-derived stem cells (hADSCs) local transplantation on orthodontically induced root resorption (OIRR) and provide theoretical and experimental basis for the clinical application of hADSCs to inhibit OIRR.
METHODS
Forty 8-week-old male Sprague Dawley rats were randomly divided into experimental group and control group, with 20 rats in each group, to establish the first molar mesial orthodontic tooth movement (OTM) model of rat right maxillary. The rats in the experimental group were injected with 25 μL of cell suspension containing 2.5×10 hADSCs on the 1st, 4th, 8th, and 12th day of modeling, while the rats in the control group were injected with 25 μL of PBS. The rat maxillary models were obtained before and after 7 and 14 days of force application, and 10 rats in each group were killed and sampled after 7 and 14 days of force application. The OTM distance was measured by stereomicroscope, the root morphology of the pressure side was observed by scanning electron microscope and the root resorption area ratio was measured. The root resorption and periodontal tissue remodeling of the pressure side were observed by HE staining and the root resorption index was calculated. The number of cementoclast and osteoclast in the periodontal tissue on the pressure side was counted by tartrate resistant acid phosphatase staining.
RESULTS
The TOM distance of both groups increased with the extension of the force application time, and there was no significant difference ( <0.05). There was no significant difference in OTM distance between the experimental group and the control group after 7 and 14 days of force application ( >0.05). Scanning electron microscope observation showed that small and shallow scattered resorption lacunae were observed on the root surface of the experimental group and the control group after 7 days of force application, and there was no significant difference in the root resorption area ratio between the two groups ( >0.05); after 14 days of application, the root resorption lacunae deepened and became larger in both groups, and the root resorption area ratio in the experimental group was significantly lower than that in the control group ( <0.05). The range and depth of root absorption in the experimental group were smaller and shallower than those in the control group, and the root absorption index in the experimental group was significantly lower than that in the control group after 14 days of force application ( <0.05). The number of cementoclast in the experimental group was significantly lower than that in the control group after 7 and 14 days of force application ( <0.05); the number of osteoclasts in the experimental group was significantly lower than that in the control group after 14 days of force application ( <0.05).
CONCLUSION
Local transplantation of hADSCs may reduce the area and depth of root resorption by reducing the number of cementoclasts and osteoclasts during OTM in rats, thereby inhibiting orthodontic-derived root resorption.
Topics: Rats; Male; Humans; Animals; Root Resorption; Rats, Sprague-Dawley; Osteoclasts; Tooth Movement Techniques; Stem Cells
PubMed: 38130198
DOI: 10.7507/1002-1892.202309030 -
PloS One 2023This study investigates the biomechanical performance of various dental materials when filled in different cavity designs and their effects on surrounding dental...
This study investigates the biomechanical performance of various dental materials when filled in different cavity designs and their effects on surrounding dental tissues. Finite element models of three infected teeth with different cavity designs, Class I (occlusal), Class II mesial-occlusal (MO), and Class II mesio-occluso-distal (MOD) were constructed. These cavities were filled with amalgam, composites (Young's moduli of 10, 14, 18, 22, and 26 GPa), and glass carbomer cement (GCC). An occlusal load of 600 N was distributed on the top surface of the teeth to carry out simulations. The findings revealed that von Mises stress was higher in GCC material, with cavity Class I (46.01 MPa in the enamel, 23.61 MPa in the dentin), and for cavity Class II MO von Mises stress was 43.64 MPa, 39.18 MPa in enamel and dentin respectively, while in case of cavity Class II MOD von Mises stress was 44.67 MPa in enamel, 27.5 in the dentin. The results showed that higher stresses were generated in the non-restored tooth compared to the restored one, and increasing Young's modulus of restorative composite material decreases stresses in enamel and dentin. The use of composite material showed excellent performance which can be a good viable option for restorative material compared to other restorative materials.
Topics: Finite Element Analysis; Composite Resins; Elastic Modulus; Glass Ionomer Cements; Dental Restoration, Permanent; Dental Stress Analysis; Stress, Mechanical
PubMed: 38128035
DOI: 10.1371/journal.pone.0295582