Osseointegration of zirconia implants compared with titanium : an in vivo study

Background Titanium and titanium alloys are widely used for fabrication of dental implants. Since the material composition and the surface topography of a biomaterial play a fundamental role in osseointegration, various chemical and physical surface modifications have been developed to improve osseous healing. Zirconia-based implants were introduced into dental implantology as an altenative to titanium implants. Zirconia seems to be a suitable implant material because of its tooth-like colour, its mechanical properties and its biocompatibility. As the osseointegration of zirconia implants has not been extensively investigated, the aim of this study was to compare the osseous healing of zirconia implants with titanium implants which have a roughened surface but otherwise similar implant geometries. Methods Forty-eight zirconia and titanium implants were introduced into the tibia of 12 minipigs. After 1, 4 or 12 weeks, animals were sacrificed and specimens containing the implants were examined in terms of histological and ultrastructural techniques. Results Histological results showed direct bone contact on the zirconia and titanium surfaces. Bone implant contact as measured by histomorphometry was slightly better on titanium than on zirconia surfaces. However, a statistically significant difference between the two groups was not observed. Conclusion The results demonstrated that zirconia implants with modified surfaces result in an osseointegration which is comparable with that of titanium implants

Malignant fibrous histiocytoma of the face: report of a case

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Increased Oral Dryness and Negative Oral Health-Related Quality of Life in Older People with Overweight or Obesity

This cross-sectional study was to evaluate the association between the oral health-related quality of life (OHRQoL) of older Thai people with obesity and oral health indicators. General and oral conditions were assessed. Oral dryness was determined using the Xerostomia Inventory-11 (XI-11) and clinical oral dryness score (CODS). OHRQoL was evaluated by the oral health impact profile (OHIP-14). Participants were aged 60–86 years; 73 (59.3%) were overweight or obese, and 50 (40.7%) were normal weight. Older patients with obesity had almost four times the rate of hypertension (OR = 3.59; 95%CI:1.34–9.60; p = 0.002), more missing teeth (p = 0.025), and higher CODS (p = 0.014) than those without obesity. The total XI-11 scores were positively associated with the total CODS, after adjusting for BMI (r = 0.267, p = 0.003). Those with obesity had almost three times the tendency for a negative OHRQoL compared with the non-obese (OR = 2.73; 95%CI:1.12–6.71; p = 0.04). After adjusting for all related factors, the chances of predicting an OHIP-14 score of four based on obesity and total XI-11 score were 4.42 (95%CI:1.57–12.47; p = 0.005) and 1.11 (95%CI:1.02–1.20; p = 0.013), respectively. Obesity had an increasingly undesirable negative impact on the OHRQoL of older Thai people and was influenced by BMI and oral dryness

In Vitro Comparison of Surgical Implant Placement Accuracy Using Guides Fabricated by Three Different Additive Technologies

Various three-dimensional (3D) printing technologies are commercially available on the market, but the influence of different technologies on the accuracy of implant-guided surgery is unclear. Thus, three printing technologies: Stereolithographic (SLA), Digital light processing (DLP), and Polyjet were evaluated in this study. An entire 30 polyurethane models replicated the clinical situation. Ten surgical guides were printed by SLA, DLP, and PolyJet. Then, implant-guided surgery was performed, and their accuracy outcomes were measured concerning angular deviation, 3D deviation at the entry point, and apex. On top of that, the total processing time was also compared. For the angular deviation, the mean deviation was not statistically significant among all technologies. For the 3D deviation, PolyJet was statistically more accurate than DLP (p = 0.002) and SLA (p = 0.017) at the entry point. PolyJet was also statistically more accurate than DLP (p = 0.007) in regards to 3D deviation at the apex. Within the limitation of this study, the deviations from the experiment showed that PolyJet had the best outcome regarding the 3D deviations at the entry point and at the apex, meanwhile, the DLP printer had the shortest processing time

Comparison of Different Types of Static Computer-Guided Implant Surgery in Varying Bone Inclinations

This research aimed to compare the accuracy of dental implant placement among three types of surgical guide: metal sleeve with key handle (Nobel guide, Nobel Biocare, Göteborg, Sweden), metal sleeve without key handle, and non-sleeve without key handle (Dentium full guide kit, Dentium Co., Seoul, Korea) when placing the implant in different bone inclinations. A total of 72 polyurethane bone models were fabricated in different inclinations (0°, 45°, and 60°). The dental implants were placed in bone models following the company’s recommendations. After dental implants were installed, the digital scans were done by an extraoral scanner. The deviations of the dental implant position were evaluated by superimposition between post-implant placement and reference model by using GOM inspect software. The deviation measurement was shown in 5 parameters: angular deviation, 3D deviation at the crest, 3D deviation at the apex, lateral linear deviation, and vertical linear deviation. The data were analyzed using One-way ANOVA and post-hoc tests at a significance level of 0.05. The accuracy of the dental implant position was not significantly influenced by the difference in the surgical guide system (p > 0.05). There were significant differences between placed and planned implant positions in the different inclinations of the bone. A significant difference was found in all parameters of 0° and 60° bone inclinations (p < 0.05). At 0° and 45°, angulated bone showed significant differences except in 3D deviation at the apex. Between 45° and 60° were significant differences only in angular deviation. Within the limitations of this study, the accuracy of implant placement among three types of surgical guides (Non-sleeve without key handle, Metal sleeve without key handle, and Metal sleeve with key handle) from two companies (Dentium and Nobel Biocare) was similar. Hence, the operators can choose the surgical guide system according to their preference. The inclination of bone can influence the angulation of dental implants

Reliability of Polyetherketoneketone as Definitive Implant-Supported Bridges in the Posterior Region—An In Vitro Study of the Ultimate Fracture Load and Vertical Marginal Discrepancy after Artificial Aging

Purpose: This study aims to investigate the ultimate fractural strength and marginal integrity of a three-unit implant-supported fixed partial denture (FPD) framework fabricated of polyetherketoneketone (PEKK) after simulated five-year clinical aging. Materials and Methods: Twelve FPD frameworks were milled (n = 6 per group). All experimental frameworks were cemented on identical stainless-steel abutment models and subjected to five years of clinically simulated thermomechanical aging. The vertical marginal gap values were analyzed using a scanning electron microscope before and after being subjected to each aging condition. A universal testing machine was used to evaluate the ultimate fracture load. Results: A significant increase in marginal gap values of the PEKK group was observed after five years of simulation aging (p p = 0.071). After thermocycling, the PEKK group showed a higher statistically significant mean marginal gap value (84.99 + 44.28 μm) than before (81.75 + 44.53 μm). The titanium group exhibited superior mechanical strength, with a fracture load significantly higher than that of the PEKK group (3050 + 385.30 and 1359.14 + 205.49 N, respectively). Conclusions: Thermocycling affects the marginal gap discrepancy of PEKK restoration. However, the mean vertical marginal gap values in PEKK and titanium groups after a five-year clinical aging simulation were clinically acceptable. The ultimate fracture load values were higher than the maximum bite force reported in the posterior region. Thus, PEKK could serve as a suitable alternative material to metal in the framework of fixed dental prostheses

Red and Yellow Injectable Platelet-Rich Fibrin Demonstrated Differential Effects on Periodontal Ligament Stem Cell Proliferation, Migration, and Osteogenic Differentiation

The biological benefits of using two fractions derived from injectable platelet-rich fibrin (i-PRF) in bone regeneration remain unclear. Thus, the current study examined two fractionation protocols producing yellow i-PRF and red i-PRF on periodontal ligament stem cells (PDLSCs). The i-PRF samples from five donors were harvested from two different levels, with and without a buffy coat layer, to obtain red and yellow i-PRF, respectively. The PDLSCs were isolated and characterized before their experimental use. The culture medium in each assay was loaded with 20% of the conditioned medium containing the factors released from the red and yellow i-PRF. Cell proliferation and cell migration were determined with an MTT and trans-well assay, respectively. Osteogenic differentiation was investigated using alkaline phosphatase and Alizarin red staining. The efficiency of both i-PRFs was statistically compared. We found that the factors released from the red i-PRF had a greater effect on cell proliferation and cell migration. Moreover, the factors released from the yellow i-PRF stimulated PDLSC osteogenic differentiation earlier compared with the red i-PRF. These data suggest that the red i-PRF might be suitable for using in bone regeneration because it induced the mobilization and growth of bone regenerative cells without inducing premature mineralization

Occlusive and Proliferative Properties of Different Collagen Membranes—An In Vitro Study

Different collagen barrier membranes come in various sources and crosslinking that may affect barrier function and tissue integration. This study investigated barrier function and tissue integration of the three different collagen membranes (Jason®: porcine pericardium, GENOSS: bovine tendon, and BioMend® Extend: cross-linked bovine tendon) with human gingival fibroblasts. The barrier function and tissue integration properties were determined under confocal microscopy. Morphological characteristics were observed using scanning electron microscopy. Our results showed that all collagen membranes allowed a small number of cells to migrate, and the difference in barrier function ability was not significant. The cross-linked characteristics did not improve barrier ability. The native collagen membrane surfaces allowed evenly scattered proliferation of HGF, while the cross-linked collagen membrane induced patchy proliferation. Statistically significant differences in cell proliferation were found between Jason and BioMend Extend membranes (p = 0.04). Scanning electron microscope showed a compact membrane surface at the top, while the bottom surfaces displayed interwoven collagen fibers, which were denser in the crosslinked collagen membranes. Within the limitations of this study, collagen membranes of different origins and physical properties can adequately prevent the invasion of unwanted cells. Native collagen membranes may provide a better surface for gingival cell attachment and proliferation

The Accuracy and Reliability of Tooth Shade Selection Using Different Instrumental Techniques: An In Vitro Study

This study aimed to investigate and compare the reliability and accuracy of tooth shade selection in the model using 30 milled crowns via five methods: (1) digital single-lens reflex (DSLR) camera with twin flash (TF) and polarized filter (DSLR + TF), (2) DSLR camera with a ring flash (RF) and polarized filter (DSLR + RF), (3) smartphone camera with light corrector and polarized filter (SMART), (4) intraoral scanner (IOS), and (5) spectrophotometer (SPEC). These methods were compared with the control group or manufacturer’s shade. The CIE Lab values (L, a, and b values) were obtained from five of the methods to indicate the color of the tooth. Adobe Photoshop was used to generate CIE Lab values from the digital photographs. The reliability was calculated from the intraclass correlation based on two repetitions. The accuracy was calculated from; (a) ΔE calculated by the formula comparing each method to the control group, (b) study and control groups were analyzed by using the Kruskal–Wallis test, and (c) the relationship between study and control groups were calculated using Spearman’s correlation. The reliability of the intraclass correlation of L, a, and b values obtained from the five methods showed satisfactory correlations ranging from 0.732–0.996, 0.887–0.994, and 0.884–0.999, respectively. The ΔE from all groups had statistically significant differences when compared to the border of clinical acceptance (ΔE = 6.8). The ΔE from DSLR + TF, DSLR + RF, SMART, and SPEC were higher than clinical acceptance (ΔE > 6.8), whereas the ΔE from IOS was 5.96 and all of the L, a, and b values were not statistically significantly different from the manufacturer’s shade (p < 0.01). The ΔE of the DSLR + RF group showed the least accuracy (ΔE = 19.98), whereas the ∆E of DSLR + TF, SMART, and SPEC showed similar accuracy ∆E (ΔE = 10.90, 10.57, and 11.57, respectively). The DSLR camera combined with a ring flash system and polarized filter provided the least accuracy. The intraoral scanner provided the highest accuracy. However, tooth shade selection deserves the combination of various techniques and a professional learning curve to establish the most accurate outcome