Tissue reaction to novel customized calcium silicate cement based dental implants. A pilot study in the dog

Objectives: The purpose of this study was to determine the level of periodontal tissue regeneration in a canine model following post-extraction placement of an implant molded from a composite material made from extracted tooth dentin and a calcium silicate cement (CSC) material. The investigation used autologous dentin in conjunction with a CSC material to form a composite implant designed for immediate tooth replacement. Methods: Two (2) beagles had a periodontal and radiographic examination performed to rule out any pre-treatment inflammation, significant periodontal disease, or mobility. Then, ination eleven (11) teeth were extracted and polyvinyl siloxane molds were made to fabricate three different types of implants: Particulate Implant (Test Group 1, n = 4), Shell Implant Alone (Test Group 2, n = 2), Shell Implant with Emdogain® (Test Group 3, n = 3). Teeth in the control group were extracted, scaled (n = 2), and then re-implanted into their respective fresh extraction sockets. At 4 weeks, a clinical, radiographic, and histologic assessment was performed. Results: Clinical evaluation revealed no mobility in any of the test or control implants and no radiographic evidence of significant bone loss or active disease. Based on the MicroCT analysis, direct bone to implant contact was observed in some areas with an apparent periodontal ligament space. Implant-related inflammation, on average, was similar among all groups, with low numbers of infiltrates. Implant-related inflammatory reaction was generally minimal and not interpreted to be adverse. Conclusion: The proposed novel composite materials revealed that not only do these materials demonstrate high biocompatibility, but also their successful integration in the alveolus is likely secondary to a partial ligamentous attachment. The current investigation may lead to the use of calcium silicate-based materials as custom dental implants. Further research on this novel composite’s biomechanical properties is necessary to develop the optimal material composition for use as a load-bearing dental implant. [Figure not available: see fulltext.

An evaluation of the effects of handpiece speed, abrasive characteristics, and polishing load on the flexural strength of polished ceramics

Statement of problem. Many studies on the strengthening effects of grinding and polishing, as well as heat treatment on ceramics, are not well standardized or use commercially available industrial polishing systems. The reported effectiveness of these strengthening mechanisms on ceramics may not be applicable to clinical dentistry. Purpose. The purpose of this study was to evaluate the effects of controlled polishing on the flexural strength of dental ceramics by using a custom-made machine that applied standardized loads and speeds that coincided with the mean loads and speeds used by experienced prosthodontists. Material and methods. A total of 140 aluminous dental ceramic bar-shaped specimens (Vitadur Alpha Enamel) measuring 1.5 x 2.0 x 25 mm were fabricated and divided into 12 groups (for most groups, n=10). Specimens were untreated, polished with different polishing systems, polished at different speeds, ground and autoglazed, polished and autoglazed, autoglazed and polished, polished with loose (paste) and bonded abrasives, or overglazed. Simulated clinical polishing was performed on the ceramic specimens by using a customized polishing apparatus that allowed independent control over the relevant polishing parameters (abrasive hardness, applied load, linear speed, rotational velocity, and wheel stiffness). Flexural strength (MPa) was measured with a 4-point bending test, and subjective surface roughness was assessed with scanning electron microscopy. Autoglazing was performed at various stages of the polishing sequence to determine the effects of polishing on surface stresses. Mean values, standard deviations, independent-sample t tests, 1-way and 2-way analyses of variance, Dunnett t tests and Kruskal-Wallis tests were applied to the data (α=.05). Results. Under a clinical load of 0.6 N for a coarse polishing wheel, 1.0 N for a medium polishing wheel, and 1.3 N for a fine polishing wheel, a linear speed of 499 mm/min, and a rotational velocity of 10,000 rpm, the use of clinical polishing instruments did not affect the flexural strength of the aluminous ceramics studied (P=.274). At higher rotational velocity (20,000 rpm), specimens polished with the diamond polishing system produced statistically weaker specimens compared with those that had been polished at 10,000 rpm (P=.019). Autoglazing treatment of the diamond-polished specimens did not reverse the strength degradation (P=.125). Conversely, diamond polishing of the autoglazed specimens resulted in significant flexural strength reduction (P=.029). Fine-diamond-bonded abrasive significantly reduced flexural strength (P=.025). Conclusions. Simulated clinical polishing at 10,000 rpm did not appear to substantially strengthen or weaken the ceramic specimens. Polishing at 20,000 rpm reduced flexural strength of the ceramic bars. Copyright © 2005 by The Editorial Council of The Journal of Prosthetic Dentistry

Fracture resistance of porcelain veneered zirconia crowns with exposed lingual zirconia for anterior teeth after thermal cycling: An in vitro study

Statement of problem: In some clinical conditions minimally invasive complete crown tooth preparations are indicated. This is especially true when gross removal of tooth structure would weaken the remaining tooth or violate the vitality of the dental pulp. Objective: The purpose of this study was to investigate the influence of (1) exposed lingual zirconia with veneered zirconia crowns, and (2) reduced lingual thickness of monolithic lithium disilicate crowns on the fracture resistance of the crowns after cyclic loading. Metal-ceramic crowns with exposed lingual metal served as controls. Materials and methods: Twenty-four maxillary central incisor crowns were fabricated in identical shape on metal testing dies in 3 groups: metal-ceramic crowns (MC, n = 8), veneered zirconia crowns (VZ, n = 8), and monolithic lithium disilicate crowns (MO, n = 8). A conservative preparation design with 0.75 mm lingual clearance was used for each crown system. All crowns were cemented to their corresponding crown preparations with self-adhesive resin cement (Multilink Automix). The crowns were subjected to 1000 cycles of thermal cycling, then cyclic loading of 111 N by means of a stainless steel ball, and 50,000 cycles of loading were applied for the fatigue test. Fatigue loading was followed by a continuously increasing compressive load, at a crosshead speed of 1 mm/min until failure. The compressive load (N) required to cause failure was recorded. Means were calculated and analyzed with one-way ANOVA and the Tukey HSD test (α = .05). Results: There was a significant difference between MO vs. MC (P = .0001), MO vs. VZ (P = .0001), and VZ vs. MC (P = .012). Conclusions: There was a significant difference in the mean fracture resistance of MC, VZ, and MO crowns in this in vitro study. The MC group recorded the highest mean fracture strength. Keywords: Zirconia crown, Zirconia thickness, Fracture strength, Lithium disilicate crow

A new reliable alternate method to an intraoral scanner (in-vitro study)

Objective: To propose a method to develop 3-dimensional (3D) models of regular and orthodontic typodonts by using their 2-dimensional (2D) images, as an alternate method to 3D scanners. Materials and methods: To propose a method to develop 3-dimensional (3D) models of regular and orthodontic typodonts by using their 2-dimensional (2D) images, as an alternate method to 3D scanners. Matierals and methods: The mandibles of two typodonts, regular occlusion and malocclusion, were scanned by using a 3D scanner to generate their models. Captured scans were used to determine the accuracy of the existing method. One hundred images of each mandible were made by using a smartphone from various angles five times to create required and generate 3D models through the software. The percentage overlap of the hard tissues of the scans and the models superimposed within the group (repeatability test), and with each other (accuracy test) gathered the proposed method\u27s accuracy and precision. The data were analyzed by using the Student\u27s t-test. Results: Ten scans and ten models were overlapped among themselves and each other and evaluated. Repeatability test; significant overlap in scans for both mandibles (regular and maloccluded), and their 3D model\u27s counterparts (P \u3c 0.05, CI 95%). Accuracy tests; significant overlap between both methods for both mandibles (P \u3c 0.05, CI 95%). Conclusion: The 2D images were successfully used to model the teeth (both regular and maloccluded) non-invasively. The proposed method showed high reproducibility as well as accuracy when compared to a commercially available 3D scanner. Clinical significance: The 3D models for both regular teeth and teeth with malocclusions were modeled by using 2D images taken with a smartphone by using the novel method which was both reproducible and accurate

Moderately Acidic pH Promotes Angiogenesis: An In Vitro and In Vivo Study

Introduction: This study evaluated the effect of different pH values of 4.4, 5.4, 6.4, 7.4, 8.4, and 9.4 on angiogenesis. Methods: Endothelial cells were isolated from the mice molar teeth and placed in 42 Matrigel (Corning, NY)-coated wells, which were prepared and divided into 6 groups (n = 7). Synthetic tissue fluid was prepared and divided into 6 parts, and their pH values were adjusted to 4.4, 5.4, 6.4, 7.4, 8.4, and 9.4. A 2-mL volume from each group was diluted in the growth medium at a ratio of 1:3 and used for tubulogenesis assay. Forty-two 6-week-old mice in 6 groups (n = 7) were used for choroidal neovascularization (CNV). A 2-μL volume from each group or saline (control) was delivered by intravitreal injection on the day of laser application and 1 week later. Data on the number of nodes, the total length of the branches, and CNV areas (μm2) were determined using ImageJ software (National Institutes of Health, Bethesda, MD) and analyzed with 1-way analysis of variance and post hoc Tukey tests. The correlation was assessed between the tested variables. Results: The number of nodes decreased with changes in pH values as follows: 6.4 \u3e 5.4 \u3e 7.4 \u3e 8.4 \u3e 9.4 \u3e 4.4. The total branch length decreased with pH value changes as follows: 6.4 \u3e 4.4 \u3e 6.4 \u3e 7.4 \u3e 8.4 \u3e 9.4, and the CNV areas decreased with pH value changes as follows: 6.4 \u3e 5.4 \u3e 4.4 \u3e 7.4 \u3e 8.4 \u3e 9.4. Conclusions: Moderately acidic pH values (5.4 and 6.4) enhanced angiogenesis, whereas moderately alkaline pH values (8.4 and 9.4) suppressed angiogenesis

Moderately Acidic pH Promotes Angiogenesis: An In Vitro and In Vivo Study

Introduction: This study evaluated the effect of different pH values of 4.4, 5.4, 6.4, 7.4, 8.4, and 9.4 on angiogenesis. Methods: Endothelial cells were isolated from the mice molar teeth and placed in 42 Matrigel (Corning, NY)-coated wells, which were prepared and divided into 6 groups (n = 7). Synthetic tissue fluid was prepared and divided into 6 parts, and their pH values were adjusted to 4.4, 5.4, 6.4, 7.4, 8.4, and 9.4. A 2-mL volume from each group was diluted in the growth medium at a ratio of 1:3 and used for tubulogenesis assay. Forty-two 6-week-old mice in 6 groups (n = 7) were used for choroidal neovascularization (CNV). A 2-μL volume from each group or saline (control) was delivered by intravitreal injection on the day of laser application and 1 week later. Data on the number of nodes, the total length of the branches, and CNV areas (μm2) were determined using ImageJ software (National Institutes of Health, Bethesda, MD) and analyzed with 1-way analysis of variance and post hoc Tukey tests. The correlation was assessed between the tested variables. Results: The number of nodes decreased with changes in pH values as follows: 6.4 \u3e 5.4 \u3e 7.4 \u3e 8.4 \u3e 9.4 \u3e 4.4. The total branch length decreased with pH value changes as follows: 6.4 \u3e 4.4 \u3e 6.4 \u3e 7.4 \u3e 8.4 \u3e 9.4, and the CNV areas decreased with pH value changes as follows: 6.4 \u3e 5.4 \u3e 4.4 \u3e 7.4 \u3e 8.4 \u3e 9.4. Conclusions: Moderately acidic pH values (5.4 and 6.4) enhanced angiogenesis, whereas moderately alkaline pH values (8.4 and 9.4) suppressed angiogenesis

C.E. Credit. Innovating Dental Education with Artificial Intelligence

ABSTRACTInnovation is at the heart of dental education, dental practice, and optimal oral health care delivery. This paper explores the opportunities and challenges of incorporating artificial intelligence (AI) in dental education. Although the scientific reporting of AI-related research in dental education is limited, the application of AI in academia and dentistry has far-reaching implications in complementing human tasks such as radiological examinations, clinical diagnoses, anatomy training, orthodontics, and prosthodontics education. Moreover, AI has the potential to assess students’ comprehension based on automated facial recognition. Sooner or later AI will change most methods of communication, which will necessitate dental schools to prepare the next generation of students to learn about these powerful tools. Its adoption has great potential for enhancing educational experiences and healthcare as well as paving the way for preparing future dentists to apply AI techniques in clinical practice. The dental community needs to implement recommended guidelines to effectively digitalize dental education with AI technologies.Continuing Education Credit Available: The practice worksheet is available online in the supplemental material tab for this article. A CDA Continuing Education quiz is online for this article: https://www.cdapresents360.com/learn/catalog/view/20

Effect of thermocycling on the surface texture and release of titanium particles from titanium alloy (Ti6Al4V) plates and dental implants: An in vitro study

Statement of problem: The release of titanium (Ti) particles from the surface of endosseous dental implants is not well understood. Purpose: The purpose of this in vitro study was to evaluate the effect of thermocycling on the surface texture and release of Ti particles from the surface of dental implants. Material and methods: Three MSI dental implants and 3 Ti alloy (Ti6Al4V) plates were divided into 6 subgroups (n=3). Specimens in each group were subjected to 0 (control group), 100, 200, 500, 1000, and 2000 thermocycles. After each cycling process, artificial saliva was collected, and the concentrations of released Ti particles were quantified by inductively coupled plasma-mass spectrophotometry (ICP-MS). The surfaces of the dental implants and Ti plates were evaluated before and after thermocycling by scanning electron microscopy (SEM), and SEM images were analyzed by using the ImageJ software program. Data were analyzed by mixed-model ANOVA and post hoc Tukey tests (α=.05). Results: The greatest Ti release was seen after 2000 thermocycles. After increasing the number of cycles, additional Ti particles were released. SEM images of the surfaces of the dental implants and Ti plates displayed significant changes in surface texture. Conclusions: Thermocycling continuously removed the protective TiO2 layer on the surface of dental implants, resulting in the release of Ti particles. The surface treatment and texture did not affect the release of Ti particles