Retention Of Long-Term Interim Restorations With Sodium Fluoride Enriched Interim Cement

Purpose: Interim fixed dental prostheses, or provisional restorations , are fabricated to restore teeth when definitive prostheses are made indirectly. Patients undergoing extensive prosthodontic treatment frequently require provisionalization for several months or years. The ideal interim cement would retain the restoration for as long as needed and still allow for ease of removal. It would also avoid recurrent caries by preventing demineralization of tooth structure. This study aims to determine if adding sodium fluoride varnish to interim cement may assist in the retention of interim restorations. Materials and methods: stainless steel dies representing a crown preparation were fabricated. Provisional crowns were milled for the dies using CAD/CAM technology. Crowns were provisionally cemented onto the dies using TempBond NE and NexTemp provisional cements as well as a mixture of TempBond NE and Duraphat fluoride varnish. Samples were stored for 24h then tested or thermocycled for 2500 or 5000 cycles before being tested. Retentive strength of each cement was recorded using a universal testing machine. Results: TempBond NE and NexTemp cements performed similarly when tested after 24h. The addition of Duraphat significantly decreased the retention when added to TempBond NE. NexTemp cement had high variability in retention over all tested time periods. Thermocycling for 2500 and 5000 cycles significantly decreased the retention of all cements. Conclusions: The addition of Duraphat fluoride varnish significantly decreased the retention of TempBond NE and is therefore not recommended for clinical use. Thermocycling significantly reduced the retention of TempBond NE and NexTemp. This may suggest that use of these cements for three months, as simulated in this study, is not recommended

Moving an incisor across the midline: A treatment alternative in an adolescent patient

A 13-year-old sought treatment for a severely compromised maxillary left central incisor and an impacted fully developed left canine. Extraction of both teeth became necessary. As the key component of the revised comprehensive treatment plan, the right maxillary central incisor was moved into the position of the left central incisor. All other maxillary teeth were moved mesially to close any gaps. Active orthodontic treatment was completed after 34 months. Frenectomy, minor periodontal surgeries, and bonded lingual retainers were used to improve aesthetics and stabilize the tooth positions. The patient was pleased with the treatment outcome. Cone-beam computed tomography provided evidence that the tooth movement was accompanied by a deviation of the most anterior portion of the median palatine suture. This observation may make relapse more likely if long-term retention cannot be ensured. Root resorption was not observed as a consequence of the major tooth movement. (Am J Orthod Dentofacial Orthop 2011;139:533-43

A tooth preparation technique in fixed prosthodontics for students and neophyte dentists

The aim of this study was to evaluate a novel technique of tooth preparation in fixed prosthodontics suitable for dental students and neophyte dentists.MATERIALS AND METHODS: Twenty-four dental students of the sixth-year class were recruited to verify the predicibility of this technique. Each student prepared two mandibular second premolars on a typodont for a dental crown with a 90° shoulder finishing line. One tooth was prepared using standard procedures taught in the prosthodontic dental course; the other tooth was prepared with the new technique. Three Professors of Prosthodontics of the same University evaluated the result on the basis of 10 criteria. RESULTS: A statistically significant difference between the two techniques was found in 8 out of 10 criteria. The new technique showed higher values (p<0.05) in 7 criteria, while the conventional technique had better results in just 1 criterion. Moreover, the total sum of values was higher for the new technique (total 41.2±3.98, p<0.05) compared to the conventional technique (total 38.12±5.18, p<0.05). CONCLUSIONS: This study showed that the results were less dependent on manual abilities and personal experience with the novel technique. It could helps dental students and neophyte dentists in their learning curve

Guidelines for the Use of Synthetic Fluid Dust Control Palliatives on Unpaved Roads

The amount of small soil particles, dust, lost from typical unpaved roads to fugitive dust is staggering. A 1 km stretch of unpaved road can contribute over 2400 kg of dust to the atmosphere (4.2 ton/mile) in a typical 3-month summer season. Road managers typically manage dust from unpaved roads with various dust-control palliatives, which are effective for up to 1 year. Synthetic fluids are a relatively new category of dust-control palliatives. Unlike the more commonly used dust-control palliatives, such as salts, engineering guidelines do not exist for the application and maintenance of synthetic fluids on unpaved roads. To fill this void, we present through this document guidelines for road design and maintenance, palliative selection, application, and care of synthetic fluid-treated roadways.Midwest Industrial Supply United States Department of TransportationReport Documentation Page .............................................................................................. ii Disclaimer ......................................................................................................................... iii List of Figures .................................................................................................................... vi Executive Summary............................................................................................................. 1 CHAPTER 1.0 – Introduction............................................................................................... 4 CHAPTER 2.0 – Background.............................................................................................. 6 Measurements of the Effectiveness of Dust Palliatives .....................................................10 CHAPTER 3.0 – Guidelines .............................................................................................. 16 Road Design and Maintenance...........................................................................................16 Palliative Selection..............................................................................................................20 Application .........................................................................................................................22 Areas Requiring Special Attention......................................................................................26 Maintenance .......................................................................................................................27 CHAPTER 4.0 – Summary................................................................................................. 31 CHAPTER 5.0 – References.............................................................................................. 3

Fracture Resistance of Zirconia Oral Implants In Vitro: A Systematic Review and Meta-Analysis

Various protocols are available to preclinically assess the fracture resistance of zirconia oral implants. The objective of the present review was to determine the impact of different treatments (dynamic loading, hydrothermal aging) and implant features (e.g., material, design or manufacturing) on the fracture resistance of zirconia implants. An electronic screening of two databases (MEDLINE/Pubmed, Embase) was performed. Investigations including > 5 screw-shaped implants providing information to calculate the bending moment at the time point of static loading to fracture were considered. Data was extracted and meta-analyses were conducted using multilevel mixed-effects generalized linear models (GLMs). The Šidák method was used to correct for multiple testing. The initial search resulted in 1864 articles, and finally 19 investigations loading 731 zirconia implants to fracture were analyzed. In general, fracture resistance was affected by the implant design (1-piece > 2-piece, p = 0.004), material (alumina-toughened zirconia/ATZ > yttria-stabilized tetragonal zirconia polycrystal/Y-TZP, p = 0.002) and abutment preparation (untouched > modified/grinded, p < 0.001). In case of 2-piece implants, the amount of dynamic loading cycles prior to static loading (p < 0.001) or anatomical crown supply (p < 0.001) negatively affected the outcome. No impact was found for hydrothermal aging. Heterogeneous findings of the present review highlight the importance of thoroughly and individually evaluating the fracture resistance of every zirconia implant system prior to market release

Jumping plant-lice of the Paurocephalinae (Insecta, Hemiptera, Psylloidea): systematics and phylogeny

Much confusion exists with respect to the content and definition of the psyUid subfamily Paurocephalinae. Based on a cladistic analysis of 22 morphological characters (16 adult and 6 larval), the subfamily is redefined to comprise the following five valid genera: Aphorma (3 species), Camarotoscena (12 valid species, with 1 new synonymy), DiC/idophlebia (= Aconopsylla, Haplaphalara, Paraphalaroida, Sinuonemopsylla and Woldaia; 24 species), Paurocephala (52 species) and Syntomoza (= Anomoterga and Homalocephata; 7 species). The tribe Diclidophlebiini is synonymised with the subfamily Paurocephalinae. The seven new generic synonymies produce 25 new species combinations. A key to genera for adults and fifth instar larvae is presented. In their revised definitions the genera exhibit relatively restricted distributions and host ranges: Aphorma: Palaearctic, Oriental - Ranunculaceae; Camarotoscena: Palaearctic - Salicaceae; Diclidophtebia: pantropical - Tiliaceae, Malvaceae, Sterculiaceae, Melastomataceae, Rhamnaceae, Ulmaceae and Euphorbiaceae; Paurocephala: Old World tropics - Moraceae, Urticaceae. Ulmaceae (all Urticales), Malvaceae. Sterculiaceae (all Malvales) and Clusiaceae (rheales); Syntomoza: Oriental, Afrotropical, Palaearctic - Flacourtiaceae, Salicaceae. The following taxa which have been referred to the Paurocephalinae are transferred to other taxa: Atmetocranium to the Calophyidae and Primascena to the Aphalaroidinae; Pseudaphorma is symonymised with Aphatara, and P. astigma with A. polygoni; the position of Strophingia is confirmed in the Strophingiinae.peer-reviewe