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There is a debate over the association between low testosterone levels in body fluids and the occurrence of chronic periodontitis (CP). The aim of the present systematic review was to assess whether low testosterone levels in body fluids reflect CP. In order to identify studies relevant to the focus question: “Is there a relationship between low testosterone levels in body fluids and CP?” an electronic search without time or language restrictions was conducted up to June 2016 in indexed databases using different keywords: periodontitis, chronic periodontitis, periodontal diseases, testosterone, and gonadal steroid hormones. A total of eight studies were included in the present systematic review. The number of study participants ranged from 24 to 1,838 male individuals with ages ranging from 15 to 95 years. Seven studies measured testosterone levels in serum, two studies in saliva, and one study in gingiva. Four studies reported a negative association between serum testosterone levels and CP. Two studies reported a positive association between decreased testosterone levels in serum and CP. Increased levels of salivary testosterone among patients with CP were reported in one study; whereas one study reported no significant difference in the concentration of salivary testosterone between patients with and without CP. One study identified significant increase in the metabolism of testosterone in the gingiva of patients with CP. Within the limits of the evidence available, the relationship between low testosterone levels and CP remains debatable and further longitudinal studies and control trials are needed.
There are different avenues for obtaining postgraduate doctoral/Ph.D. degrees in Germany and abroad. Depending on their interests and career plans, candidates can choose a postgraduate doctorate/Ph.D. that focuses on a career in academia or a doctorate that does not involve all elements of a Ph.D. and is obtained for the title’s sake. Germany offers this type of diversity and flexibility, whereas the USA postgraduate doctorate model presents a more structured doctorate. The current article provides insight regarding various and more flexible pathways for obtaining a postgraduate doctorate by comparing the German and the American model. The diversity of academic degrees in dentistry and medicine, such as postgraduate doctoral degrees and the higher postdoctoral degrees available in Germany for graduates interested in academia, makes educational evaluation processes and credentials recognition challenging. The lack of transparency and a systematic approach for the academic acknowledgment of the different scientific values of each doctorate type is creating confusion, primarily when German postgraduate doctorate holders pursue academic careers internationally. The current article aims to enhance the knowledge about the different academic degrees and facilitate the educational evaluations, specialty applications, and employment processes. Understanding the additional scientific value of each doctorate type offered in Germany is imperative for their credential recognition internationally.
Six dentin adhesives were tested in vitro regarding their cytotoxicity on human fibroblasts. The adhesives Hybrid Bond, One-up Bond F Plus, AdheSE, Clearfil SE Bond, Optibond Solo Plus and Syntac were eluted with culture medium as single or sequentially applied adhesive part for 24 h. 75 Petri dishes were produced per group. They were evaluated triangulated, comprising the quantitative evaluation (105 ones) to determine “viable”, “dead” and “debris” cells with the use of a cell-counter and the reactivity index was also identified based on the qualitative assessment (420 ones). One-up Bond F Plus, AdheSE and Clearfil SE Bond showed a statistical difference of viable cells to the cell control. For One-up Bond F Plus, statistically, differences compared to hybrid bond and Syntac were also found. All the adhesives except One-up Bond F Plus showed significant differences between single and sequentially applied adhesive part regarding the quantitative evaluation. The test material showed a moderate grade of cytotoxicity. As a result, a statistically significant difference of the cytotoxicity between the self-etch and etch-and-rinse adhesives cannot be demonstrated regarding the qualitative evaluation and the reactivity index, but the differences between sequentially applied and single applied components can be proved.
Potential causes of titanium particle and ion release in implant dentistry : a systematic review
(2018)
Implant surface characteristics, as well as physical and mechanical properties, are responsible for the positive interaction between the dental implant, the bone and the surrounding soft tissues. Unfortunately, the dental implant surface does not remain unaltered and changes over time during the life of the implant. If changes occur at the implant surface, mucositis and peri-implantitis processes could be initiated; implant osseointegration might be disrupted and bone resorption phenomena (osteolysis) may lead to implant loss. This systematic review compiled the information related to the potential sources of titanium particle and ions in implant dentistry. Research questions were structured in the Population, Intervention, Comparison, Outcome (PICO) framework. PICO questionnaires were developed and an exhaustive search was performed for all the relevant studies published between 1980 and 2018 involving titanium particles and ions related to implant dentistry procedures. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for the selection and inclusion of the manuscripts in this review. Titanium particle and ions are released during the implant bed preparation, during the implant insertion and during the implant decontamination. In addition, the implant surfaces and restorations are exposed to the saliva, bacteria and chemicals that can potentially dissolve the titanium oxide layer and, therefore, corrosion cycles can be initiated. Mechanical factors, the micro-gap and fluorides can also influence the proportion of metal particles and ions released from implants and restorations.
Interaction of gold nanoparticles (AuNPs) in the vicinity of cells’ membrane with a pulsed laser (λ = 532 nm, τ = 1 ns) leads to perforation of the cell membrane, thereby allowing extracellular molecules to diffuse into the cell. The objective of this study was to develop an experimental setting to deliver molecules into primary human gingival fibroblasts (pHFIB-G) by using ns-laser pulses interacting with AuNPs (study group). To compare the parameters required for manipulation of pHFIB-G with those needed for cell lines, a canine pleomorphic adenoma cell line (ZMTH3) was used (control group). Non-laser-treated cells incubated with AuNPs and the delivery molecules served as negative control. Laser irradiation (up to 35 mJ/cm2) resulted in a significant proportion of manipulated fibroblasts (up to 85%, compared to non-irradiated cells: p < 0.05), while cell viability (97%) was not reduced significantly. pHFIB-G were perforated as efficiently as ZMTH3. No significant decrease of metabolic cell activity was observed up to 72 h after laser treatment. The fibroblasts took up dextrans with molecular weights up to 500 kDa. Interaction of AuNPs and a pulsed laser beam yields a spatially selective technique for manipulation of even primary cells such as pHFIB-G in high throughput.
The IPS e.max system by Ivoclar Vivadent, offering a variety of products and indications, is widely used for all-ceramic restorations. We analyzed the clinical track record of these products in daily clinical practice, associating their restorative survival rate with various parameters to define recommendations for long-term stability. A total of 1058 full-coverage crowns and fixed partial dentures (FPDs) were evaluated retrospectively over up to 66.48 (37.05 ± 18.4) months. All were made of IPS e.max Press, IPS e.max CAD, IPS e.max Ceram or IPS e.max ZirPress and had been delivered by a private dental practice within three years. Uses not recommended by the manufacturer were also deliberately included. The five-year cumulative survival was 94.22% (i.e., 94.69% or 90.58% for glass-ceramic crowns or FDPs and 100% or 90.06% for zirconia-based crowns or FDPs). Significantly superior outcomes emerged for conventional vs. adhesive cementation and for vital vs. non-vital abutment teeth, but not for recommended vs. non-recommended uses. Caution is required in restoring non-vital teeth, but the spectrum of recommended uses should generally be reconsidered and expanded, given our finding of high survival and success rates for IPS e.max ceramics, even for uses not currently recommended by the manufacturer.
Background. The placement of an implant in a previously infected site is an important etiologic factor contributing to implant failure. The aim of this case report is to present the management of retrograde peri-implantitis (RPI) in a first maxillary molar site, 2 years after the implant placement. The RPI was treated using an air-abrasive device, Er,Cr:YSGG laser, and guided bone regeneration (GBR).
Case Description. A 65-year-old Caucasian male presented with a draining fistula associated with an implant at tooth #3. Tooth #3 revealed periapical radiolucency two years before the implant placement. Tooth #3 was extracted, and a ridge preservation procedure was performed followed by implant rehabilitation. A periapical radiograph (PA) showed lack of bone density around the implant apex. The site was decontaminated with an air-abrasive device and Er,Cr:YSGG laser, and GBR was performed. The patient was seen every two weeks until suture removal, followed by monthly visits for 12 months. The periapical X-rays, from 6 to 13 months postoperatively, showed increased bone density around the implant apex, with no signs of residual clinical or radiographic pathology and probing depths ≤4 mm.
Conclusions. The etiology of RPI in this case was the placement of an implant in a previously infected site. The use of an air-abrasive device, Er,Cr:YSGG, and GBR was utilized to treat this case of RPI. The site was monitored for 13 months, and increased radiographic bone density was noted.
Manufacturing processes of custom implant abutments may contaminate their surfaces with micro wear deposits and generic pollutants. Such particulate debris, if not removed, might be detrimental and provoke inflammatory reactions in peri-implant tissues. Although regulatory guidelines for adequate cleaning, disinfection, or sterilization exist, there does not appear to be a consistent application and data on the amount and extent of such contaminants is lacking. The aim of the present in vitro study was to evaluate the quality and quantity of processing-related surface contamination of computer-aided design/computer-aided manufacturing (CAD/CAM) abutments in the state of delivery and after ultrasonic cleaning. A total of 28 CAD/CAM monotype and hybrid abutments were cleaned and disinfected applying a three-stage ultrasonic protocol (Finevo protocol). Before and after cleaning, the chemical composition and the contamination of the abutments were assessed using scanning electron microscopy (SEM), dispersive X-ray spectroscopy(EDX),andcomputer-aidedplanimetricmeasurement(CAPM).Inthedeliverycondition, monotype abutments showed a significantly higher amount of debris compared to hybrid abutments (4.86±6.10% vs. 0.03 ± 0.03%, p < 0.001). The polishing process applied in the laboratory after bonding the hybrid abutment components reduces the surface roughness and thus contributes substantially to their purity. The extent of contamination caused by computer-aided manufacturing of custom abutments can be substantially minimized using a three-stage ultrasonic protocol.
Locator® and ball attachments are well-established systems to attach overdentures to two inter-foraminal implants. This study aimed to evaluate differences between the two systems regarding prosthetic maintenance and patients' oral-health-related quality of life (OHRQoL). Dental records of patients with a mandibular implant-retained overdenture were retrospectively analyzed. Prosthetic maintenance measures involving the denture suprastructure and attachment matrix and patrix were analyzed. Furthermore, the Oral Health Impact Profile-G14 (OHIP-G14) was used to evaluate OHRQoL. Results were analyzed by means of Kaplan–Meier analysis and Student's t- and log-rank tests. The records of 122 patients were evaluated. Kaplan–Meier survival analysis revealed a significant difference between ball attachments (Group B; n patients = 47) and Locator® attachments (Group L; n patients = 75) regarding the occurrence of denture fractures (p < 0.001) and events affecting the matrix (p = 0.028) and patrix (p = 0.030). Group L had a significantly lower total OHIP-G14 score than Group B (p = 0.002). The most common maintenance events were matrix-related and denture relining for both attachment systems. Group B required more maintenance measures than Group L. Moreover, patients in Group L had better OHRQoL than patients in Group B.
Background. The purpose of this systematic review was to accurately assess the procedural success of ridge preservation technique through the application of strict inclusion and exclusion criteria.
Data Sources. A methodical search of PubMed of the US National Library of Medicine and the Cochrane Central Register of Controlled Trials was conducted for applicable articles. Only randomized controlled trials comparing ridge preservation treatment with a nongrafting control, ten-subject minimum sample size, and three or more months of follow-up were included in our study.
Types of Studies Reviewed. In a screening between January 1980 and September 2017, articles meeting predetermined criteria were further examined in a qualitative data analysis. A thorough search of the databases provided 1876 articles. Of these records, 174 were assessed for eligibility through the systematic employment of inclusion and exclusion criteria.
Results. Two records were appropriate for further data analysis. One study used a mixture of a deproteinized cancellous bovine bone and porcine collagen fibers in a block form (DBB/CF), while the other study used leukocyte-platelet-rich fibrin (L-PRF). The use of DBB/CF reduced the magnitude of vertical bone resorption, yet the study showed high risk of bias. The use of L-PRF reduced the magnitude of both the horizontal and vertical crestal bone resorption; however, the low sample size created wide standard deviations between the test and control groups. Inherent weaknesses were present in both studies. Through methodical analysis of both records, the dissimilarities prevented the conduction of a meta-analysis.
Implications of Key Findings. Within the limitations of this systematic review, L-PRF reduced the magnitude of vertical and horizontal bone resorption, which places L-PRF as a potential material of choice for ridge preservation procedures. Conclusions. Within the limitations and weaknesses of both studies, the use of DBB/CF prevented the vertical crestal bone resorption while the L-PRF prevented both the horizontal and vertical crestal bone resorption. More randomized controlled clinical trials are needed to eliminate all the confounding factors, which bias the outcome of ridge preservation techniques.
