Intraosseous heat generation during guided osteotomy for dental implantological purposes

Prosthodontically driven implant surgery has been subject of interest to dental professionals for the past decade. The correct positioning of implants has a number of obvious advantages, such as favourable functional and aesthetic outcomes, better occlusion and less chance of implant overload, to mention just a few. A well-positioned implant can also make it easier for the patient to maintain good oral hygiene, once the superstructure has been inserted. Thermal osteonecrosis, thermal damage as the application of metal implants has become routine in musculoskeletal trauma surgery, orthopaedic surgery, spine surgery, cranio-maxillofacial surgery, dentistry and oral implantology, drilling of bone has also become one of the most common basic surgical steps. As for the healing of the osseous structure, this can be influenced by several factors including implant design, chemical composition, the material and shape of the implant, the physiological characteristics of the host bone bed, loading conditions, the topography of the implant surface, the healing potential of the host bone, the use of adjuvant treatments, pharmacological agents and also heat generation during osteotomy. The bone tissue is very vulnerable to thermal injury, and the temperature threshold for tissue survival during osteotomy is 47˚C when drilling is maintained for more than 1 minute. Therefore, it is critical for successful osseointegration to keep heat generation under control during osteotomy. Excess heating above this limit can lead to the primary failure to of osseointegration. In the last few years a rapid development could be observed in the field of computer-assisted implant placement. Increased beneficial use of computers was made possible through the recent advances in computer technology, which allowed the planning and the execution of various steps involved in dental reconstructions during the placement of dental implants. The above mentioned novel possibilities include computer assistance for the planning of surgical interventions, for the implementation of the surgical steps, for capturing intraoral situation and also for designing temporary and final prosthetic solutions or even for the manufacturing of prosthetic components. Combining the cone-beam computed tomography (CBCT) images with an implant planning software has made it possible to virtually plan the optimal implant positions, in regard of the future prosthetic needs and the vital anatomical structures. This information can be used to fabricate a drill guide, which ultimately results in the transfer of the planned implant position from the computer to the patient, with the guide directing both the osteotomy and the insertion of the implant. The present thesis sought to find answers to the following questions: 1. How does the effect of the combination of low-speed drilling and cooled irrigation fluid influence intraosseous temperature elevation during guided and freehand implant surgery? Our hypothesis was that with the combination of low-speed and cooled irrigation fluid we can control the temperature increment in such a way that with any of the drilling procedures it will be avoidable to do thermal damage to the bony structure. 2. How does drill wear and consequent intraosseous temperature elevation during freehand and guided bone drilling change, with special attention to the effect of metal-on metal contact during guided drilling? We hypothesized that the metal-on-metal contact would damage the surface of the drilling bits, and therefore it would be associated with significantly higher temperatures during the drilling procedures..

Insights on carbapenem-resistant Acinetobacter baumannii : phenotypic characterization of relevant isolates

Acinetobacter baumannii (A. baumannii) is an important nosocomial pathogen, which may be a causative agent in a wide-range of human pathologies. Carbapenems are usually considered the last safe and effective choice of drugs for the treatment of Gram-negative infections. The emergence of carbapenem-resistant A. baumannii (CRAB) is a critical public health issue as they leave clinicians with limited therapeutic options. In this study, phenotypic methods were used to characterize sixty-two (n = 62) A. baumannii isolates, which were included based on their suspected non-susceptibility to meropenem. Minimum inhibitory concentrations (MICs) of meropenem, levofloxacin, gentamicin, sulfamethoxazole/trimethoprim, tigecycline were determined using E-tests, while colistin MICs were determined using broth microdilution. The isolates were subjected to the modified Hodge test (MHT), the modified carbapenem-inactivation method (mCIM) and the imipenem/EDTA combined disk test (CDT). Efflux pump overexpression was studied using agar plates containing phenylalanine-arginine β-naphthylamide (PAβN). Assessment of biofilm-formation was carried out using the crystal violet tube-adherence method. 64.5% of the strains showed meropenem MICs in the resistant range (>8 mg/L), resistance rates were similarly high to the other tested antibiotics. The MHT and mCIM assay were positive in 79.0% and 67.7% of cases, respectively; the presence of an MBL was suggested for 29.0% of isolates. Efflux-pump overexpression was seen in 12.9% of isolates. 54.8% of the isolates were characterized as strong biofilm-producers. Microbiology laboratories have an important role in differentiating the distinct mechanisms by which these pathogens develop the CRAB phenotype, as plasmid-borne carbapenemases are significant from the standpoint of public health microbiology

Healthcare Professionals’ Practice of HIV Post-Exposure Prophylaxis in Clinical Settings in Karachi, Pakistan

The human immunodeficiency virus (HIV) is an important public health concern that has become more prevalent in Pakistan in recent decades. Healthcare professionals (HCPs) are frequently exposed to many HIV-infected patients; as a result, they are more vulnerable to HIV infection due to occupational exposure. Hence, the current study was executed to evaluate HCPs’ knowledge, attitude and practice in terms of post-exposure prophylaxis (PEP) for HIV. This cross-sectional study was carried out in several clinical and laboratory settings of Karachi and the HCPs involved in treating patients were surveyed using a structured questionnaire. The Shapiro–Wilk test was performed to establish the normality of the variables. Pearson correlation was employed to identify the relationship between the independent variables considering p-values < 0.05 as statistically significant. A total of 578 filled forms were incorporated in the study with a response rate of 72.2%. Physicians and medical students (OR = 1.68; 95% CI = 1.16–2.24; p = 0.001) belonging to private work settings (OR = 1.84; 95% CI = 1.33–2.35; p < 0.003) indicated better knowledge. The majority, 407 (70.4%), of the respondents reported having been exposed to risky occupational circumstances during their professional life; however, 65.7% took PEP for HIV after exposure and only 56.8% completed the entire course. A statistically significant association was observed between experience (p = 0.004, CI = 0.14–0.72), job category (p = 0.0001, CI = 0.16–0.62) and frequency of exposure (p = 0.003, CI = 0.42–11.31) and reporting of occupational exposure. More than half (53.8%) of respondents stated that their institute has a policy for the management of HIV exposures; however, their response was significantly associated with their organization (p = 0.004). The current study shows adequate knowledge revealing a positive attitude among respondents; however, there was a gap between the knowledge and its practical application. Even though many of the HCPs had experienced risky HIV exposure, a lack of reporting was noted in the study

Navigáció alkalmazása az implantológiában

A vizsgálat célkitűzése a statikus navigációs rendszerek pontosságának elemzése volt a nemzetközi irodalmi adatok alapján. Elektronikus irodalomkutatást végezve 661 publikációt találtunk a témában. A keresési feltételeknek legjobban megfelelő 139 absztrakt áttekintését követően 52 publikáció teljes elemzéséből 24 olyan tanulmányt választottunk ki, amelyek az implantátumok pozíciójának pontosságára vonatkozó adatokat tartalmaztak. A kiválasztott források közül tizennégy klinikai, tíz pedig in vitro (modell, cadaver) vizsgálat volt. Az adatok összehasonlítását varianciaanalízissel (Tukey-féle post-hoc teszt; p < 0,05) végeztük. 2819 esetet összesítve a belépési értékek átlaga 0,98 mm volt. Az apikális eltérések tekintetében ez a szám 1,29 mm volt, míg a szögeltéréseket vizsgálva 3,96o-ot kaptunk eredményül. Szignifikáns eltérést sikerült kimutatni az egyes behelyezési (részlegesen, és teljesen sablon által irányított) módszerek között az apikális távolság, belépési eltérés és a szögeltérés alapján. Az egyes paraméterek további vizsgálatára egy, illetve több vizsgálati központban zajló randomizált, kontrollált klinikai kísérletek szükségesek, amelyek megfelelnek az evidencia alapú tudás követelményeinek