Effect of proper oral rehabilitation on general health of mandibulectomy patients

Introduction Reduced oral aperture and mandibular opening are relatively common problems, which have a wide variety of causes [1]. Limited access to the oral cavity can be problematic for patients and dental professionals [2]. According to Glossary of Prosthodontics terms GPT [3], reduced oral aperture is defined as microstomia, which is a term used to describe any congenital or acquired reduction in the size of the oral opening that is severe enough to compromise esthetic, deglutition, nutrition, and quality of life [4]. The mandible is the key bone involved in face esthetic, mastication, and speech. Surgical resection of the mandible (known as a mandibulectomy) is often performed for tumors of the head and neck area, which should be followed by oral rehabilitation (i.e., occlusal adjustments and replacement of missing teeth and/or soft tissues, if involved) [5]. The treatment of oral tumors such as squamous cell carcinomas may require mandibular resection to secure adequate margins [6]. Segmental resection of the mandible leads to significant patient illness if not properly managed. Mandibulectomy can lead to loss of mandibular support to the teeth, inadequate mastication, impaired speech and disfigurement of the face [7]

Fracture strength and fractographic analysis of zirconia copings treated with four experimental silane primers

This study evaluated and compared the effect of new four experimental silane coupling agents on ‎the fracture strength of zirconia copings. The findings were supported with fractographic and ‎finite element analyses. All together 125 zirconia copings with a wall thickness of 0.6mm were ‎fabricated on identical nickel-chromium master dies and then divided randomly into five groups ‎‎(n = 25). Four test groups were prepared according the experimental silane primer (labeled: ‎OIWA1, OIWA2, OIWA3 and OIWA4) and one ontrol group without silanization. The silane ‎monomers used were: 3-methacryloxypropyltrimethoxysilane (in OIWA1), 3-‎acryloxypropyltrimethoxysilane (in OIWA2), 3-isocyanatopropyltriethoxysilane (in OIWA3) and ‎styrylethyltrimethoxysilane (in OIWA4). Tribochemical sandblasting (silica-coating) treatment ‎was performed to the inner surface of the copings in the test groups. All the specimens were ‎silanized at the inner surfaces of the zirconia copings. Self-adhesive universal resin cement was ‎used to cement the copings to the underlying master die. Zirconia copings were vertically loaded ‎on the cusp area until the first crack failure was occurred using Precision Universal Tester at a ‎constant crosshead speed of 1 mm/min. Then, the machine was manually controlled to cause ‎more failure to further determine the texture of fracture. Three dimensional finite element ‎analysis and fractography were performed to support the fracture strength findings. Based on the ‎finite element analysis results, zirconia silanized with 3-acryloyloxypropyltrimethoxysilane ‎showed the highest fracture strength with a mean of 963.75N (SD 4.5 N), while zirconia copings ‎silanized with 3 methacryloyloxypropyltrimethoxysilane showed a mean fracture strength value ‎of 925.65N (SD 2.4 N). Styrylethyltrimethoxysilane-silanised zirconia showed mean fracture ‎strength of 895.95N (SD 3.5 N). Adding silane coupling agents to the resin-zirconia interface ‎increased the fracture strengths significantly (ANOVA, p < 0.05). Silanization with four new ‎experimental silane primers in vitro produced significantly greater fracture strength than the ‎control group not treated with the test silane.

Performance Evaluation of Roughened Solar Air Heaters for Stretched Parameters

Artificial roughness applied to a Solar Air Heater (SAH) absorber plate is a popular technique for increasing its total thermal efficiency (&eta;t&minus;th). In this paper, the influence of geometrical parameters of V-down ribs attached below the corrugated absorbing plate of a SAH on the &eta;t&minus;th was examined. The impacts of key roughness parameters, including relative pitch p/e (6&ndash;12), relative height e/D (0.019&ndash;0.043), angles of attack &alpha; (30&ndash;75&deg;), and Re (1000&ndash;20,000), were examined under real weather conditions. The SAH &eta;t&minus;th roughened by V-down ribs was predicted using an in-house developed conjugate heat-transfer numerical model. The maximum SAH &eta;t&minus;th was shown to be 78.8% as predicted under the steady-state conditions of Re = 20,000, solar irradiance G = 1000 W/m2, p/e = 8, e/D = 0.043, and &alpha; = 60. The result was 15.7% greater efficiency compared to the default smooth surface. Under real weather conditions, the &eta;t&minus;th of the roughened SAH with single- and double-glass covers were 17.7 and 20.1%, respectively, which were higher than those of the smooth SAH

EPA-coated titanium implants promote osteoconduction in white New Zealand rabbits

OBJECTIVES: To investigate the effect of eicosapentaenoic acid (EPA)-coated Ti implants on osteoconduction in white New Zealand rabbit mandibles. MATERIAL AND METHODS: Sandblasted and cleansed planar titanium specimens with a size of 5 × 5 × 1 mm were coated on one side with 0.25 vol% eicosapentaenoic acid (EPA). The other side of the specimens was kept highly polished (the control side). These specimens were inserted in rabbit mandibles. Twelve rabbits were randomly assigned into three study groups (n = 4). The rabbits were sacrificed at 4, 8, and 12 weeks. The harvested specimens with the implants were assessed for new bone formation on both sides of the implant using CBCT, conventional radiographs, and the biaxial pullout test. The results were statistically analyzed by a nonparametric Kruskal-Wallis test and Friedman's test as multiple comparisons and by Brunner-Langer nonparametric mixed model approach (R Software). RESULTS: A significant osteoconductive bone formation was found on the EPA-coated Ti implant surface (P < 0.05) at 8 weeks when compared to the polished surface (control). Biaxial pullout test results showed a significant difference (P < 0.05) after 8 and 12 weeks with a maximum force of 243.8 N, compared to 143.25 N after 4 week. CONCLUSION: EPA implant coating promoted osteoconduction on the Ti implant surfaces, enhancing the anchorage of the implant to the surrounding bone in white New Zealand rabbits

Manual for pre-clinical removable prosthodontics

DENTURE PROSTHODONTICS ‘Complete denture prosthodontics’ is defined as that body of knowledge and skills pertaining to the restoration of the edentulous arch with a removable dental prosthesis. While ‘complete denture prosthetics’ is defined as: 1. the replacement of the natural teeth in the arch and their associated parts by artificial substitutes 2. the art and science of the restoration of an edentulous mouth The complete denture treatment is the restoration of a completely edentulous (no teeth) by an artificial substitute called “Complete denture” which is the replacement of the upper (maxillary) and lower (mandibular) lost teeth by an appliance that may replace the lost teeth and their associated adjacent structure. The complete denture treatment is a treatment that deals with a pathological case, of having no teeth that renders the patient lacking the function of cutting the food as well as being psychologically disturbed of having the cosmetic corruption of the appearance of the face by losing the muscular support of the facial expression. The complete denture could be considered unique when compared to other prostheses replacements in the body, since it deals with both function and appearance, or in other words it deals with the physiology and psychology. Replacing missing teeth is a technical as well as a clinical procedure, a denture cannot be thought of like any other part of the body that can be worn or fitted according to size as no denture of one patient can fit another patient’s mouth even if they were twins. 7 The clinical part of the treatment is to obtain the informative anatomical landmarks from the patient oral cavity by the dentist, and transfer it to the laboratory where the technical part is taken over by the technician. The clinical and the technical aspects of the complete denture fabrication have got an ample intermingling relation that makes the dentist as well as the technician, scientifically and technically attentive of the work of the other. The complete procedure of making a denture should be made clear to the dental student prior to the clinic attendance, thus preparing the student to be fully aware of both the technical (preclinical) as well as the clinical aspects of the treatment and by mastering both it will be possible to understand the sequential steps and their consequences

Indoor Radon Concentration Measurement in Selected Factories in Northern and Central Iraq

In this work, the outdoor radon concentration level and lung cancer risks have been measured in selected locations in northern and central Iraq during the summer season 2012 by using time integrated passive radon dosimeters containing LR-115 Type II plastic track detectors. These measurements were carried out in the factories for an exposure time of 60 day. The radon concentration in these factories ranges from (36.36 – 125.10) Bq.m-3 with an average of (59.93Bq.m-3), which within the acceptable radon levels (50-150) Bq.m-3 recommended by the International Commission on Radiological Protection (ICRP). The average absorption effective dose equivalent for a person living in factories for which the investigation were done was found to be (1.425mSv.y-1). It is observed that the average lung cancer per year per 106 person was found to be 25.654. Keyword: LR-115 Type II nuclear track detectors; Radon concentration; AEDE; PAEC

Study the Effect of Parameters on Tire-Pavement Interaction Noise (TPIN)

The present study was prepared to determine the effect of different parameters on tire-pavement Interaction noise (TPIN). TPIN was calculated utilizing the Onboard Sound Intensity Method (OBSI) using apparatus Lutron 801 sound level meter single probe 1 kHz of one microphone is placed at the right back test tire with a specific distance. A total of 30 sections were selected for the main roads in Baghdad city, with 134 meters for each test section in length. TPIN data was calculated for various parameters such as different pavement types, various test vehicles, different speeds (40, 56, and 72) km/h, various types of tires, different pavement aging, and different mean texture depth (MTD) values Which is measured by a sand patch test. The sound intensity dBA increases when MTD value and vehicle speed increase in both types of pavements. On the other hand, the sound intensity dBA increases when age increases for asphalt pavement type while it decreases in asphalt concrete pavement type. In addition, the sound intensity dBA in the asphalt pavement type is lower than in the asphalt concrete pavement when compared to the condition of the new pavement. The opposite is in the case of old pavement surfaces. As well as, the sound intensity dBA in Bus is greater than in the passenger car, and the silver stone tire is lower than the Dunlop tire in the passenger car. Finally, it is concluded that TPIN may be reduced or increased due to the effect of different parameters

Structural, electrical and magnetic properties of BiFe1-xYxO3 (0 ≤ x ≤ 0.6) ceramics

The effect of Y substitution on the microstructure, dielectric, magnetic and leakage current properties of BiFe1-xYxO3 (0 ≤ x ≤ 0.6) ceramics was investigated. The BiFeO3 phase that is dominant at x = 0.0 – 0.2 decreased with the increase of Y substitution. Other phases such as YFeO3 and Bi1.46Y0.54O3 emerged with Y substitution and became dominant in the range x = 0.3 – 0.4 and 0.5 – 0.6, respectively. The BiFe1-xYxO3 composites of rounded shape grains at x = 0.0 deformed at x = 0.1 – 0.3 and changed to melted-like grains at x = 0.4 – 0.6 with the incorporation of smaller grains at x = 0.5 and 0.6. The sample with x = 0.2 had the highest remnant magnetization (Mr = 0.09 emu/g) and saturation magnetization (Ms = 2.9 emu/g). The sample with x = 0.4 showed the highest dielectric constant of 104 and lowest loss tangent of 1.34 × 10-4. The leakage current was significantly reduced to a lower value of 2.80 × 10-8 A/cm2 at x = 0.6