Zirconia implant abutments : a review

Objectives: An increasing aesthetic demand within developed populations conducted to the fabrication of metalfree restorations and to a wide use of ceramic materials, due to its excellent characteristics of biocompatibility and aesthetics. With the incessant increase of commercial labels involved in this technological advance, a review is imposed on ceramic abutments, specifically on zirconia. We made a search of articles of peer-reviewed Journals in PubMed/ Medline, crossing the terms ?Dental Abutments?, ?Dental Porcelain? and ?Zirconia?. The review was divided by subtopics: zirconia physical and mechanical properties, precision fit in the implant-abutment interface, zirconia abutments strength and, finally, bacterial adherence and tissues response. Several studies demonstrate that zirconia abutments offer good results at all the levels but relevant issues need further studies and evaluation. One of the most important is the clinical long term success of zirconia abutments on implants, given that in the literature there are no sufficient in vivo studies that prove it

Preload loss of abutment screws after dynamic fatigue in single implant-supported restorations. A systematic review

To carry out a systematic literature review of the causes of preload loss of the abutment screws, of internal and external connection implants, tightened to different torque values and subjected to cyclic loading. A systematic search was conducted in PubMed, EMBASE, and Cochrane Library databases with reference to in vitro studies in which internal and external connection implants were subjected to cyclic loads to determine the degree of loosening of the abutment screws after loading. The reviewed studies tested distinct implant connections (mostly externally hexed, and morse taper) subjected to diverse cycles (from 16667 to 1 million), with loads ranging from 0-400 Nw, using screws of different materials and designs that were tightened into torques between 20-45 Ncm, Accordingly after loading the percentage of torque loss ranges between 16.1% to 39%. Most of the studies indicate that the internal connection, together with the morse taper, best resists cyclic loading in terms of screw loosening in single-tooth implants

Measuring [Ca2+] in the endoplasmic reticulum with aequorin

Producción CientíficaThe photoprotein aequorin was the first probe used to measure specifically the [Ca2+] inside the lumen of the endoplasmic reticulum ([Ca2+]ER) of intact cells and it provides values for the steady-state [Ca2+]ER, around 500 M, that closely match those obtained now by other procedures. Aequorin-based methods to measure [Ca2+]ER offer several advantages: (i) targeting of the probe is extremely precise; (ii) the use of low Ca2+-affinity aequorin allows covering a large dynamic range of [Ca2+], from 10−5 to 10−3 M; (iii) aequorin is nearly insensitive to changes in Mg2+ or pH, has a high signal-to-noise ratio and calibration of the results in [Ca2+] is made straightforward using a simple algorithm; and (iv) the equipment required for luminescence measurements in cell populations is simple and low-cost. On the negative side, this technique has also some disadvantages: (i) the relatively low amount of emitted light makes difficult performing single-cell imaging studies; (ii) reconstitution of aequorin with coelenterazine requires previous complete depletion of Ca2+ of the ER for 1–2 h, a maneuver that may result in deleterious effects in some cells; (iii) because of the high rate of aequorin consumption at steady-state [Ca2+]ER, only relatively brief experiments can be performed; and (iv) expression of ER-targeted aequorin requires previous transfection or infection to introduce the appropriate DNA construct, or alternatively the use of stable cell clones. Choosing aequorin or other techniques to measure [Ca2+]ER will depend of the correct balance between these properties in a particular problem

El humorismo de piedad en la narrativa breve de Leopoldo Alas, <<Clarín>>

Universidad de Sevilla. Grado en Filología Hispánic

Caries and quality of life in portuguese adolescents : impact of diet and behavioural risk factors

The aim of this study was to assess the impact of diet and behavioural risk factors on caries appearance, and on oral health-related quality of life (OHRQoL) among Portuguese adolescents. An epidemiological study conducted on 782 adolescents between 11-17 years, from randomly selected public schools of the 3rd cycle of basic education. All participants were asked for self-perceived general status health, about tooth-brushing habits and about the using of toothpaste with fluoride and a Food Frequency Questionnaire. The DMFT index (decayed, missing and filled teeth) was evaluated according to WHO criteria. To evaluate the OHRQoL, the 49-items Oral Health Impact Profile questionnaire (OHIP-49) was applied. Consumption more than once a week of tea with sugar, milk with sugar and biscuits were significantly associated with DMFT index. Lower levels in OHRQoL was reported by students who consumed frequently (more than once a week) fast food, chocolate flakes and those who brushed their teeth once a day or less frequently instead of 2-3 times a day. Frequency of consumption of sweetened/fast food was a significant factor associated with caries and quality of life

Implant loss and crestal bone loss in early loading versus delayed and immediate loading in edentulous mandibles. A systematic review and meta-analysis

Information about the risk of early loss and crestal bone loss of dental implants which have been loaded early is scant if compared with data available for those conventionally or immediately loaded. A meta-analysis of early loss and crestal bone loss i

Validation the Oral Health Impact Profile (OHIP-14sp) for adults in Spain

Objectives: The oral health-related quality of life indicators are increasingly used to measure the impact of oral conditions on quality of life to complement clinical data in cross-sectional and longitudinal studies. One of the most internationally spread indi- cators is the Oral Health Impact Profile (OHIP-14), but it has still never been applied in Spain. The aim of this study was to validate the OHIP-14 for use among adults in Spain. Study design: A cross-sectional study was performed in Granada (Spain). A consecutive sample (n=270) of the Regional Government staff visiting the Employment Risk Prevention Centre for a routine medical check-up participated in this study. All participants self-completed the piloted OHIP-14sp and were examined according to World Health Organization methodology for caries, periodontal disease and prosthesis. Reliability analyses and validity tests were carried out to evaluate the psychometric properties of the OHIP-14sp by using two different methods of total scoring (i.e. the Additive and the Simple Count). Results: The reliability coefficient (Cronbach ́s alpha) of the OHIP-14sp was above the recommended 0.7 threshold and considered excellent (alpha: 0.89). Some subjective factors (perceived dental treatment need, complaints about mouth and self-rated oral satisfaction) were strongly associated with both total scoring methods of the OHIP-14sp, supporting the criterion, construct and convergent validity. Moreover the impact levels were mainly influenced by caries data, e.g., number of teeth requiring extraction (r = 0.21; p<0.01) and number of decayed visible teeth (between premolars) (r = 0.17; p<0.01). The prevalence of impacts was 80.7% using the occasional or more frequently threshold. The most prevalently affected OHIP domains were “psychological discomfort” (53.7%), “functional limitation” (51.1%) and “physical pain” (42.2%). Conclusions: The OHIP-14sp is a precise, valid and reliable instrument for assessing oral health-related quality of life among adult population in Spain

Electromyographic and patient-reported outcomes of a computer-guided occlusal adjustment performed on patients suffering from chronic myofascial pain

Objectives: Muscular hyperactivity is a potential source of symptoms in patients with temporal-mandibular disorders. An adequate occlusal adjustment may relieve such symptoms. This study aims to measure the effect of shortening the protrusive disclusion time (DT) and balancing the center of occlusal forces (COF) on the EMG recordings and assess the pain reported by chronic patients one month after the computer-guided occlusal adjustment. Study Design: The sample studied comprised 34 patients suffering from chronic facial pain in which the EMG activity of both masseters was recorded by electromyography. By selective grinding we alleviated all the occlusal interferences during the mandibular protrusion from the habitual closure position in order to establish an immediate posterior disclusion and an equilibration of the COF. Results: At follow-up 76.5% of the patients reported no facial pain. Moreover, the EMG activity and protrusive DT were significantly reduced, and occlusal and muscular function were significantly more symmetric than at baseline. Conclusions: According to this EMG study, this computer-guided occlusal adjustment is able to reduce the activity of the masseters and the self-reported muscular pain of patients one-month after treatment

The occupational role of dental conditions among a consecutive sample of Spanish workers

Objectives: To assess the occupational impact of the mouth in terms of days of work loss in the last year and the perception of the working performance disturbance because of the oral conditions. Study design: A consecutive sample (n=269) of the Regional Government staff of the province of Granada (Spain) was recruited. Participants were asked about work loss related to health problems in the past 12 months, capturing the aetiological entities, the frequency of the work absent and the total days loss. Also subjects reported if they believed that mouth affects their occupational performance, and if they have perceived difficulties for carrying out work because of the mouth. Data on sociodemographic, behavioural and clinical factors were also gathered. Chi-squared test, Odds ratio (OR) and relative risk (RR) of perceived occupational role were used to quantify the effect of the modulating factors. Results: Almost 40% of individuals were absent from work during the last year spending on average 5.4 days for recovering. Colds and musculoskeletal pathology were the major causes of sick leave. Dental disease caused short work absences (4 days on average) only in 2.8% of participants. However most of workers (62.5%) considered mouth to influence their occupational performance, mainly because of the pain-related events (61.7%), but only 4.1% of workers reported difficulties in carrying out their work in the past 12 months. Females (RR=1.3), participants attending regular dental visits (RR=1.4) and denture wearers (RR=2.5) were shown to have significantly higher risk of perceiving an occupational role of the mouth. Those workers reporting that mouth influences their work have significantly poorer oral health than counterparts. Conclusions: Most workers considered that mouth influences their occupational performance but dental disease has demonstrated to be a minor occupational cause of sick leave in terms of prevalence and magnitude of work loss. © Medicina Oral S. L