A Retrospective Evaluation of 5 Years of Clinical Results of Metal-Ceramic vs. Monolithic Zirconia Superstructures in Maxillary All-on-4TM Concept.

The aim of the current study was to present the clinical and radiological outcomes of monolithic zirconia superstructures compared to the metal-ceramic ones in the All-on-4 concept for the prosthetic rehabilitation of the maxillae. A total of 30 patients were subdivided into groups according to their superstructure type (metal-ceramic (n = 15) or monolithic zirconia (n = 15)). All implants were functionally loaded within 24 h after insertion with provisional acrylic superstructures. Prosthetic complications, marginal bone loss, plaque accumulation, probing pocket depth, bleeding on probing, and bite force were documented over a period of 5 years. Marginal bone loss around the implants of the ceramic group remained well over the five years (1.21 ± 0.23 mm). However, marginal bone loss was significantly lower around the implants in the monolithic zirconia group (0.22 ± 0.14 mm) (p < 0.001). Bleeding on probing, plaque accumulation, and probing pocket depth values were correlated with marginal bone loss. Among all evaluated parameters, no differences could be detected in terms of the angulation of the implants. Detachment or chipping was observed in seven cases in the metal-ceramic superstructure group. In all cases, dentures were removed and repaired in the laboratory. In the monolithic zirconia group, chipping was detected after one year in two cases, after two years in four cases, and after five years in one case and could be managed by polishing in situ. Monolithic zirconia superstructures presented superior results regarding the parameters evaluated.

Investigation of Topographical Alterations in Titanium-Zirconium-Alloy Implant Threads following Er:YAG Irradiation.

The aim of the current experimental study was to comparatively assess the surface alterations in titanium and titanium-zirconium alloy implants in terms of thread pitch topography after irradiation with an Er:YAG laser, which is recommended in the literature for its sterilizing effect in the treatment of contaminated implant surfaces. Roxolid® and SLA® (Sand-blasted, Large-grit, Acid-etched) implants from Straumann® company with the same macro topography were investigated. The surface treatment was carried out using a wavelength of 2940 nm, 60 s irradiation time, a frequency of 10 Hz, and energies between 120 mJ and 250 mJ. The alterations were quantitatively analyzed by conducting roughness analysis via white light interferometry and qualitatively using SEM images. Roxolid® could particularly maintain its surface topography at a level of 160 mJ. At an energy level of 250 mJ, the surface properties of the pitch could be significantly altered for the first time. Compared to the Standard Plus dental implants studied, no distinct removal of the material from the surface was detected. The alloy properties of Roxolid® confirm the manufacturer's statement in terms of stability and could offer advantages in peri-implantitis management if decontamination has been selected. However, as a part of a respective strategy, smoothening of a Roxolid® implant surface requires a significantly higher energy level compared to SLA-Standard® dental implants.

Adapting a simple surgical manual tool to a 3D printed implantology protocol: the use of a universal screwdriver for fixation of custom-made laser sintered titanium subperiosteal implants.

PURPOSE: Current paper aims to describe a simple technique used for the fixation of the screws of a customized implant via a universal screw driver (BoneTrust® Easy Screw according to Dr. Bayer, Medical Instinct®, GmbH, Germany) to simplify the surgical placement of the customized implants. METHODS: The insertion of the drilling screws for the retention of the implant with angulated handpiece into the palatinal region or zygomatic buttress were performed with universal screw driver. RESULTS: The retention screws could be inserted with a proper angulation without interfering with the surrounding tissues. The technique described herein has significantly simplified the surgical intervention. CONCLUSION: The insertion of the drilling screws for the retention of the implant with angulated handpiece into the palatinal region or zygomatic buttress could be challenging, thus the anatomical structures and the insufficient length of the handpiece could interfere with the placement of the screw with a proper angulation. This problem could be easily managed with the use of universal screw driver.

Comparative Assessment of the Primary Stability of Straumann BLX Implant Design Using an In Vitro Sinus Lift-Simultaneous Implant Insertion Model.

Straumann BLX is a novel implant system that has been proclaimed to provide an ideal primary stability in all types of bone. In the current study, the primary stability of the Straumann BLX implant systems with Straumann tapered effect (TE) implants have been comparatively assessed in bovine ribs by using a simultaneous sinus elevation and implant insertion model. In the study group, BLX (4.0 × 12 mm), TE (4.1 × 12 mm), BLX (4.5 × 12 mm), and TE (4.8 × 12 mm) were placed in each bony window, which resembles the sinus maxillaris. As a control, BLX and TE implants with the same sizes were inserted into the proximal diaphysis of the bovine ribs. A total of 40 implant insertions were performed. Stability was measured with resonance frequency analysis. In the study group, 4.8-mm TE implants showed significantly higher values compared with 4.5-mm BLX implants (P = .116). However, 4.0-mm BLX implants in the control group showed higher stability compared with 4.0-mm-diameter TE (P = .014). The primary stability of the BLX implants in the control group was significantly higher compared with the experimental group in both widths (P= .018 for BLX 4.0 mm and P = .002 for BLX 4.5 mm, respectively). The use of the TE design with a wide diameter in simultaneous implant placement with sinus lift could present higher implant stability quotient values and might be a more appropriate option for implant recipient sites with poor bone volume and quality. However, the advantage of BLX design in standard implant insertion protocols could be of value.

The Impact of COVID-19 Vaccination on Anxiety Levels of Turkish Dental Professionals and Their Attitude in Clinical Care: A Cross-Sectional Study.

BACKGROUND: The current study aimed to assess the anxiety and fear levels and the attitude towards clinical care, such as the use of personal protective equipment and number of patients examined, before and after COVID-19 vaccination among Turkish dental professionals. METHODS: A questionnaire including socio-demographical characteristics and clinical data regarding the number of patients, the use of personal protective equipment, vaccine confidence interval, positive or negative COVID-19 diagnosis, and fear and anxiety levels were examined. RESULTS: A total of 475 dentists (196 men and 279 women) participated. Overall, the vaccination had a positive effect on the decrease of fear and anxiety levels of dental professionals. It was observed that the number of interventional procedures significantly increased after vaccination. Besides that, the amount of personal protective equipment used in patients, especially after the vaccination, has decreased. CONCLUSION: Despite the positive effects of vaccination on the anxiety levels of dental professionals, protective measurements should further be the main concern, regardless of the vaccination status of both the dental professional and the patient.

Six-year clinical outcomes of implant-supported acrylic vs. ceramic superstructures according to the All-on-4 treatment concept for the rehabilitation of the edentulous maxilla.

The aim of the current study was to document the long-term clinical results of the use of two prosthetic techniques for the rehabilitation of completely edentulous maxillae according to the "All-on-Four" concept: Fixed, screw-retained prosthesis mounted on a chrome-molybdenum framework with (1) metal-ceramic veneers and (2) Acrylic prosthesis with acrylic resin prosthetic teeth. A total of 34 patients were assigned to subgroups according to their own preference of the superstructure type (ceramics [n: 17] or acrylic resin [n: 17]). Prosthetic complications, marginal bone loss, plaque accumulation, bleeding on probing, bite force and oral-health-related quality of life were assessed over a period of 6 years. Marginal bone loss around implants of the ceramic group remained well within the limits for 'success', as defined by the 2007 Pisa consensus over the time (1.43 ± 0.35 mm). However, marginal bone loss was significantly more pronounced around the implants in the acrylic group (2.15 ± 0.30) and the difference between two groups was statistically significant (p: 0.00). Bleeding on probing and plaque accumulation showed also positive correlation with marginal bone loss. Both acrylic and ceramic suprastructures appeared to be equivalent after 6 years; however, ceramic suprastructures revealed superior clinical results in terms of bone loss and plaque accumulation. Current study determines the long-term clinical outcomes of different prosthetic management alternatives in All-on-Four and aids to increase dental professionals' ability to meet the patients' expectations.

Marine Algae Incorporated Polylactide Acid Patch: Novel Candidate for Targeting Osteosarcoma Cells without Impairing the Osteoblastic Proliferation.

Biodegradable collagen-based materials have been preferred as scaffolds and grafts for diverse clinical applications in density and orthopedy. Besides the advantages of using such bio-originated materials, the use of collagen matrices increases the risk of infection transmission through the cells or the tissues of the graft/scaffold. In addition, such collagen-based solutions are not counted as economically feasible approaches due to their high production cost. In recent years, incorporation of marine algae in synthetic polymers has been considered as an alternative method for preparation grafts/scaffolds since they represent abundant and cheap source of potential biopolymers. Current work aims to propose a novel composite patch prepared by blending Sargassum vulgare powders (SVP) to polylactide (PLA) as an alternative to the porcine-derived membranes. SVP-PLA composite patches were produced by using a modified solvent casting method. Following detailed material characterization to assess the cytocompatibility, human osteoblasts (HOBs) and osteosarcoma cells (SaOS-2) were seeded on neat PLA and SVP-PLA patches. MTT and BrdU assays indicated a greater cytocompatibility and higher proliferation for HOBs cultured on SVP-PLA composite than for those cultured on neat PLA. SaOS-2 cells cultured on SVP-PLA exhibited a significant decrease in cell proliferation. The composite patch described herein exhibits an antiproliferative effect against SaOS-2 cells without impairing HOBs' adhesion and proliferation.

Awareness and Knowledge of SARS-CoV-2 Infection among Dental Professionals According to the Turkish National Dental Guidelines.

The objective of the current survey was to assess the awareness of the dental professionals according to the principals described by the Turkish Dental Association (TDA). A questionnaire including the socio-demographic data, specialties/academic degree, institutions/affiliations, the knowledge about COVID-19, the number of patients examined and dental treatments performed during the COVID-19 pandemic, the knowledge of protection based on the guidelines described by TDA, contamination with COVID-19 and the psychological complaints has been used. A total of 947 (63.1%) dentists enrolled the study. The results showed satisfactory knowledge about the COVID-19 etiology, mode of transmission and the pre-procedural cautions as the majority of them had a fair level of knowledge with significantly higher knowledge among specialized respondents. The participants have also recorded a good judgment towards performing the emergency dental treatment during the current COVID-19 pandemic which corresponds with the guidelines determined by TDA. Considering the updates on the transmission of COVID-19 and protective strategies, there is an urgent need for improvement of dentists' knowledge about risk assessment via training programs. The incidence of positive testing among dental professionals also necessitates immediately testing of asymptomatic Turkish dental professionals.

Assessment of marginal integrity of five different polymers in retrograde root-end filling following apicoectomy: An in-vitro analysis with scanning electron microscope and micro-radiography.

PURPOSE: The aim of the study was to evaluate marginal adaptation properties of five different sealers used as root filling material. MATERIALS: Apical resection was performed on 100 canals of 50 maxillary premolars in slaughtered pigs. The root end of 24 canals were retrogradely filled with Diaket™, 37 root canals with Super-EBA™ including 18 with Super-EBA™. Regular and 19 with Super-EBA™ fast, 20 canals with ProRoot® MTA and 19 canals with AH-Plus™. For quantitative examination, scanning electron microscope (SEM) analysis and for qualitative examination, microradiography was performed. RESULTS: Diaket™ achieved an overall average of 4.872 microns gap value as the best result. The mean values of marginal gap widths of AH-Plus™ and Super-EBA™ were almost with 8.044 microns and 9.951 microns in about the same magnitude, followed by Super-EBA™ Regular with 11,560 microns. Highest marginal gap value was found for ProRoot® MTA with 18.343 microns ( p < 0.001). CONCLUSIONS: Both in terms of its marginal integrity and material properties, Diaket™ is the most suitable material for retrograde obturation. A preliminary version of the current paper could be found at www.researchsquare.com/article/rs-6198/v1.

Histological Aspects of a Novel Technique Used for the Management of Infections Secondary to Sinus Bone Grafting.

Recently, a technical note describing a promising method for the management of infections after sinus bone grafting by irrigating the corresponding area with hydrogen peroxide based solution with an aid of a drain has been published. The aim of this paper was to present the histological and radiological results of the above mentioned technique. A total of 17 patients who have presented with infections secondary to sinus bone grafting enrolled in the study. During implant placement, bone was collected from the originally grafted site with a trephine burr for radiological examination via micro-computed tomography and histological examination. According to the results of the current study, Bio-Oss acted as a scaffold, and mature fibrous bone formed trabeculae, which assembled to an interlinked trabecular structure. Average results obtained from the microradiography confirmed the higher percentage of Bio-Oss (27.21% ±â€Š3.31%) at the corresponding area; whereas the amount of newly formed bone was slightly lower (6.79% ±â€Š1.13%) As a conclusion, this simple and minimally invasive technique might be beneficial in avoiding removal of bone graft material and could help in rescuing the former laborious procedure.

A clinical study on the 6-year outcomes of immediately loaded three implants for completely edentulous mandibles: "the all-on-3 concept".

The objective of the current study was to demonstrate the 6-year clinical and radiological treatment outcomes of the technique performed by immediately loading of three implants (single straight in the mid-line and two tilted distal implants) for the management of total edentulous mandibles and introduce a simple decision matrix for selection of the most appropriate protocol in cases with insufficient length of the interforaminal area. Re-assessments were performed over a total observation period of 6 years after surgery via measurement of bone resorption around implants, bleeding on probing, plaque accumulation, periodontal probing depth, bite force measurements and oral health impact profile. A total of 29 patients (45% women and 55% men) with a mean age of 65 ± 6 years enrolled in the study. 14 patients received an acryl-based bridge as definitive prosthetic restoration and 15 patients received a ceramic-based restoration. Both during the immediate loading phase and during the 6-year follow-up, there was no implantation loss. Regardless of the implant position, all implants showed continuous bone loss over the observation time. The bone loss around dental implants during observation period was only maximum 1.0 ± 1 mm and it remained well within the limits for 'success' according to the 2007 Pisa consensus (< 2 mm). The plaque index showed no significant fluctuations between the implant positions and the individual examination times. The approach described herein might help the surgeon by avoiding unnecessary loss of bone strength, selecting implant sites, and establishing the biomechanical advantage of increased A-P spread for immediate function.

The expression of melanoma-associated antigen A (MAGE-A) in oral squamous cell carcinoma: an evaluation of the significance for tumor prognosis.

OBJECTIVES: Melanoma-associated antigens A had been detected repeatedly in oral squamous cell carcinoma, but not in healthy mucosa. Additionally, patients with MAGE-A expressing cancers are regarded to have a worse survival prognosis, so that MAGE-A are supposed to be part of carcinogenesis. Which role these antigens fulfill within OSCC is still, up today, largely unknown. This study examines the hypothesis that MAGE-A is being produced in OSCC but not in mucosa tissue and if MAGE-A has any correlation to clinical patient's parameters like tumor size, lymph node metastasis, distant metastasis, overall survival, and recurrence. MATERIALS AND METHODS: For this purpose, 50 tumor samples and 39 mucosa samples were analyzed by means of PCR and immunohistochemical staining with the antibody 6C1. RESULTS: Forty of 41 stained tumor samples showed a positive antibody reaction with a maximum staining rate of 53%. Sixteen mucosa samples showed a mild positive reaction. The PCR revealed a linear expression pattern of MAGE-A in which the genes are proportionally expressed in OSCC. We did not find any relationship between MAGE-A and tumor size, overall survival, or recurrence. There was also no connection between MAGE-A and tumor parameters Hif-1 and LDH. Their expression was detected tendentially in tumors with higher staging, advanced lymph node metastasis, and rising age of the patients. The genes MAGE-A3+6 and MAGE-A4 had a statistically significant correlation with lymph node metastasis (p = 0.007 and p = 0.004). Patients got distant metastasis and influence of MAGE-A on metastatic behavior could not be verified. The genes MAGE-A3 and -A4 are consequently qualified as tumor markers in the field of diagnosis and follow-up of OSCC. CONCLUSIONS AND CLINICAL RELEVANCE: Two genes have great potential as target proteins in immunotherapy. The genes MAGE-A3+6 and MAGE-A4 had a statistically significant correlation with lymph node metastasis.

A 5-year prospective clinical trial on short implants (6 mm) for single tooth replacement in the posterior maxilla: immediate versus delayed loading.

The aim of this paper was to demonstrate the treatment outcomes following immediate functional loading concept of short implants inserted for single tooth replacement in the posterior maxilla. The study was performed on 63 patients who received short (6 mm) implants for single tooth replacement in the posterior maxilla. Forty-eight patients underwent immediate functional concept, whereas 15 of the implants were loaded 3 months after insertion. The patients were evaluated for up to 5 years after prosthesis completion. The endpoints included the evaluation of implant survival rate, crown length, bone resorption, plaque accumulation (PI), bleeding on probing (BOP), periodontal probing depth (PPD) and assessment of oral health impact profile (OHIP). At the end of the follow-up period of 5 years, three implants (6.3%) from the immediate loading group have failed during the observation period. Bone loss was significantly lower in the delayed loading group compared to the immediately loaded implants. At the end of the second year, BOP values were higher in the immediately loaded group. Throughout the observation period, PI values in the group with immediate loading were higher. PPD increased consistently and during the first 3 years in the immediate loading group. As a conclusion, short implants inserted for single tooth replacement at the posterior maxilla presented with satisfactory clinical outcomes in both immediate and delayed loading concepts. However, immediately loaded implants presented with an increased bone loss and higher BOP values. As assessed by the OHIP score, a subjective improvement was observed in both groups without significant differences.

Cytotoxic and inflammatory effects of alendronate and zolendronate on human osteoblasts, gingival fibroblasts and osteosarcoma cells.

OBJECTIVE: The aim of this paper was to assess the effects of zoledronate (ZOL) and alendronate (FOS) on apoptotic behavior and gene expression of pro- and inflammatory cytokines of three cell types (human osteoblasts, human gingival fibroblasts and human osteogenic sarcoma cell lines) during a period of 4 weeks. MATERIAL AND METHODS: Cell viability and proliferation was assessed via cell proliferation test (MTT), fluorescence diacetate analysis (FDA). Expression of inflammatory cytokines was investigated by using polymerase chain reaction. RESULTS: The proliferation and cell vitality of osteoblasts and fibroblasts were negatively affected in a dose dependent manner under ZOL and FOS administration. Osteosarcoma cells showed an increase in proliferation under lower doses of BP. ZOL had a significantly higher cytotoxic effect compared with FOS on osteoblasts and fibroblasts. ZOL increased the production of IL-6 in all cell types, whereas FOS only in osteosarcoma cell, which happened in dose dependent manner. Bisphosphonates could result in increase of IL-1ß expression of fibroblasts. An increase of IL-12 was observed at higher doses of ZOL administration among osteoblasts and FOS administration in osteosarcoma cells. CONCLUSION: ZOL and FOS could encourage cytotoxic and inflammatory reactions.

A comparative study on 7-year results of "All-on-Four™" immediate-function concept for completely edentulous mandibles: metal-ceramic vs. bar-retained superstructures.

The study aims to document the clinical outcomes over a 7-year period of two techniques used for the rehabilitation of edentulous mandibles according to the "All-on-Four™" concept: (1) fixed complete-arch prostheses fabricated with metal-ceramic implant-supported fixed prosthesis with a titanium framework and all-ceramic crowns and (2) bar-retained implant-supported removable prosthesis with acrylic resin prosthetic teeth. The study was performed on 32 patients who received immediately loaded "All-on-Four™" fixed mandibular prostheses. (Fixed prostheses with ceramic superstructures, n:16; bar-retained removable acrylic prostheses, n:16). The patients were evaluated for up to 7 years after prosthesis completion. The endpoints included the evaluation of prosthodontic complications, bone resorption, plaque accumulation, bleeding on probing, periodontal probing depth and an oral health impact profile (OHIP). Bone loss remained under 1.2 mm in all of the implants, and no difference was observed between two groups. Plaque accumulation increased gradually in both groups, and the bar-retained acrylic-bearing implants showed significantly higher values during the first 5 years. Immediate improvement was assessed by the OHIP score in both groups. The observed bone loss and the subjective outcomes showed equivalent levels of clinical success for bar-retained and ceramic superstructures over a 7-year period. The higher level of plaque accumulation observed around implants with bar-retained superstructures requires that patients with acrylic superstructures be highly motivated to maintain their personal oral hygiene. Further studies are needed to clarify the occurrence of prosthodontic complications and assess their economic aspects.

Vestibuloplasty with Retroauricular Skin Grafts for Dental Implant Rehabilitation in Vascularized Fibula Grafts: Two Case Reports.

The aim of this study was to present the use of retroauricular full-thickness skin grafts in vestibuloplasty surgeries for dental implant rehabilitation in vascularized fibula grafts. Two patients underwent mandibular reconstruction with vascularized fibula grafts due to mandibular gunshot injuries. Inadequate sulcus gaps secondary to mandibular soft tissue deficiencies were managed by full-thickness autologous skin grafts harvested from the retroauricular region. Dental rehabilitation was achieved by implants placed in free fibula grafts. In both cases, complete graft survival was achieved. Cosmetic and functional outcomes were satisfactory. Owing to its high resiliency and elasticity and its thin and hairless structure, full-thickness retroauricular skin graft is an effective treatment modality in the management of intraoral soft tissue deficiencies. Patients with gunshot injuries present great functional and esthetic demands, and every report presenting new treatment modalities is helpful in the management of the condition.

Correlation between resonance frequency, insertion torque and bone-implant contact in self-cutting threaded implants.

The aim of this study was to evaluate the correlation between resonance frequency analysis (RFA) values and the histomorphometric bone-implant contact (BIC) immediately after insertion of the implant. Additionally, it was examined to define which extent peak insertion torque (PIT) was correlated with the latter measurements. 15 Xive® S plus root from dental implants were inserted in fresh porcine frontal bones. The insertion torque was measured with the Kavo Intrasurg 300 surgical unit. RFA connector was coupled to the implants and the mean value of 20 consecutive RFA measurements was calculated via Osstell® ISQ device. The implants were removed with the adjacent bone with a band saw. The blocks were processed for undecalcified histology. Two perpendicular longitudinal middle sections of the implant were made and stained with toluidine blue and the BIC was assessed by histomorphometry. The correlation coefficient (Spearman) between RFA and BIC was R = 0.579 (p = 0.026, F test). The correlation between PIT and BIC (0.33, p > 0.05) and PIT and RFA (0.153, p > 0.05) was not statistically significant. The present data confirmed a moderate and statistically positive correlation between RFA and BIC. No correlation between BIC and PIT and PIT and RFA was observed. Further studies considering different bone qualities would be beneficial in understanding the relation between RFA and BIC.

Longitudinal micro-computed tomography monitoring of progressive liver regeneration in a mouse model of partial hepatectomy.

The partial hepatectomy (PH) model is widely used to study liver regeneration. Currently, the extent of regeneration is analyzed by measuring the weight of the liver post-mortem or by magnetic resonance imaging. In this study we aimed to determine whether liver volume gain can be accurately measured using micro-computed tomography (microCT). Approximately 42% of the liver was removed by ligation in C57BL/6 N mice. Mice were divided into two study groups. In group 1 conventional characterization of liver hyperplasia was performed by weighing the liver post-mortem. In group 2, liver volume gain was determined by microCT volume estimation. MicroCT results showed equivalent regeneration rates compared with the conventional method without the need to mathematically determine initial liver weights before PH. This parameter is strongly influenced by the age, strain and sex of the mice. In addition non-invasive microCT determination of volume gain over multiple time-points using the same animal reduces the number of animals needing to be used (in line with the 3R principle of replacement, reduction and refinement).