2,654 research outputs found

    Moving Teeth Faster, Better and Painless. Is It Possible?

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    Autopilot? A reflexive review of the piloting process in qualitative e-research

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    Purpose: This paper examines an oft-neglected aspect of qualitative research practice – conducting a pilot – using the innovative approach of ‘e-research’ to generate both practical and methodological insights. Approach: Using the authors’ ‘e-research’ pilot as a reflexive case study, key methodological issues are critically reviewed. This review is set in a broader context of the qualitative methods literature in which piloting appears largely as an implicit practice. Using a new and emerging approach (‘e-research’) provides a prompt to review our ‘autopilot’ tendencies and offers a new lens for analysing research practice. Findings: We find that despite an initial focus on ‘practical’ aspects of data collection within our ‘e-research’, the pilot opened up a range of areas for further consideration. We review research ethics, collaborative research practices and data management issues specifically for e-research but also reflect more broadly on potential implications for piloting within other research designs. Practical implications: We aim to offer both practical and methodological insights for qualitative researchers, whatever their methodological orientation, so that they might develop approaches for piloting that are appropriate to their own research endeavours. More specifically, we offer tentative guidance to those venturing into the emerging area of ‘e-research’. Value: This paper offers insight into an oft-ignored aspect of qualitative research, whilst also engaging in emerging area of methodological interest

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

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    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

    The Paradigm of the Relationship Among Occlusion, Orthodontics and Temporomandibular Disorders

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    The relationship between occlusion, Orthodontics and temporomandibular disorders have been subject of discussions and controversies. In the past, the scientific literature stated that the temporomandibular disorders occurred due to the malocclusion, and, for its correction, an orthodontic treatment should be performed. Apparently, those theories have become obsoletes, and according to more consistent scientific articles, the relationship among these entities have been questioned. This literature review shows a possible change in the paradigm of the relationship among the three entities

    Intra- and inter-examiner Reliability of Direct Facial Soft Tissue Measurements Using Digital Calipers

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    Background: The objective of this study is to determine if facial soft tissue measurements using digital calipers can be reliably taken by the same examiner and by a large group of examiners. Materials and Methods: Ten examiners performed a set of 18 in-clinic measurements on 10 female and 10 male dental students using a digital caliper twice over a 3-week period. The intra-class correlation coefficient and the Shrout-Fleiss method were used for the statistical analysis. Results: Anthropometric intra-examiner reliability was high for all measurements (none fell below R = 0.934). However, inter-examiner reliability exhibited a wide range of values, some reliable (nasal width at widest nostrils [R = 0.922] and subnasale to upper lip [R = 0.926]), and others unreliable [base of nose (R = 0.590), mouth height (R = 0.585), and soft tissue B point to gnathion (R = 0.623)]. Conclusions: Soft tissue measurements of clearly identifiable points measured by the same examiner produced highly consistent, accurate and reliable measurements. Soft tissue points with poor definition resulted in average-to-poor reliabilities measurements

    Bonding with Self-etching Primers – Pumice or Pre-etch? An \u3cem\u3ein vitro\u3c/em\u3e Study

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    The purpose of this study was to compare the shear bond strengths (SBSs) of orthodontic brackets bonded with self-etching primer (SEP) using different enamel surface preparations. A two-by-two factorial study design was used. Sixty human premolars were harvested, cleaned, and randomly assigned to four groups (n = 15 per group). Teeth were bathed in saliva for 48 hours to form a pellicle. Treatments were assigned as follows: group 1 was pumiced for 10 seconds and pre-etched for 5 seconds with 37 per cent phosphoric acid before bonding with SEP (Transbond Plus). Group 2 was pumiced for 10 seconds before bonding. Group 3 was pre-etched for 5 seconds before bonding. Group 4 had no mechanical or chemical preparation before bonding. All teeth were stored in distilled water for 24 hours at 37°C before debonding. The SBS values and adhesive remnant index (ARI) score were recorded. The SBS values (±1 SD) for groups 1–4 were 22.9 ± 6.6, 16.1 ± 7.3, 36.2 ± 8.2, and 13.1 ± 10.1 MPa, respectively. Two-way analysis of variance and subsequent contrasts showed statistically significant differences among treatment groups. ARI scores indicated the majority of adhesive remained on the bracket for all four groups. Pre-etching the bonding surface for 5 seconds with 37 per cent phosphoric acid, instead of pumicing, when using SEPs to bond orthodontic brackets, resulted in greater SBSs

    Lateral cephalometric analysis of asymptomatic volunteers and symptomatic patients with and without bilateral temporomandibular joint disk displacement

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    Few studies of dentofacial and orthodontic structural relationships relative to temporomandibular joint (TMJ) dysfunction have been reported. We undertook this investigation to determine any correlation of orthodontic and dentofacial characteristics with TMJ bilateral disc displacement. The population of patients was selected from a TMJ clinic where a control group of asymptomatic volunteers had been previously established and standardized. Differences in skeletal structural features were determined among three study groups: (1) asymptomatic volunteers with no TMJ disk displacement, (2) symptomatic patients with no TMJ disc displacement, and (3) symptomatic patients with bilateral TMJ disk displacement. Thirty-two asymptomatic volunteers without disk displacement (25 female, 7 male) were compared with the same number each of symptomatic patients without TMJ disk displacement and symptomatic patients with bilateral TMJ disk displacement. All subjects had undergone a standardized clinical examination, bilateral TMJ magnetic resonance imaging, and lateral cephalometric radiographic analysis. The groups were matched according to sex, TMJ status, age, and Angle classification of malocclusion. Seventeen lateral cephalometric radiographic cranial base, maxillomandibular, and vertical dimension variables were evaluated and compared among the study groups. The mean angle of SNB, or the intersection of the sella-nasion plane and the nasion–point B line (indicating mandibular retrognathism relative to cranial base), of the symptomatic patients-with-displacement group was significantly smaller than that in the asymptomatic volunteers and symptomatic patients without bilateral disk displacement (p \u3c 0.05). Female subjects showed smaller linear measurements of mandibular length, lower facial height, and total anterior facial height than male subjects in all three groups (p \u3c 0.05). The mean angle of ANB, or the intersection of the nasion–point A and nasion–point B planes (indicating retrognathism of mandible relative to maxilla), was significantly greater in female than in male subjects, in all groups (p \u3c 0.05). Symptomatic patients with bilateral disk displacement had a retropositioned mandible, indicated by a smaller mean SNB angle compared with that in asymptomatic volunteers and symptomatic patients with no disk displacement on either side. Lateral cephalometric radiographic assessment may improve predictability of TMJ disk displacement in orthodontic patients but is not diagnostic; nor does the assessment explain any cause-and-effect relationship. (Am J Orthod Dentofacial Orthop 1998;114:248-55.

    Bonding with Self-etching Primers – Pumice or Pre-etch? An \u3cem\u3ein vitro\u3c/em\u3e Study

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    The purpose of this study was to compare the shear bond strengths (SBSs) of orthodontic brackets bonded with self-etching primer (SEP) using different enamel surface preparations. A two-by-two factorial study design was used. Sixty human premolars were harvested, cleaned, and randomly assigned to four groups (n = 15 per group). Teeth were bathed in saliva for 48 hours to form a pellicle. Treatments were assigned as follows: group 1 was pumiced for 10 seconds and pre-etched for 5 seconds with 37 per cent phosphoric acid before bonding with SEP (Transbond Plus). Group 2 was pumiced for 10 seconds before bonding. Group 3 was pre-etched for 5 seconds before bonding. Group 4 had no mechanical or chemical preparation before bonding. All teeth were stored in distilled water for 24 hours at 37°C before debonding. The SBS values and adhesive remnant index (ARI) score were recorded. The SBS values (±1 SD) for groups 1–4 were 22.9 ± 6.6, 16.1 ± 7.3, 36.2 ± 8.2, and 13.1 ± 10.1 MPa, respectively. Two-way analysis of variance and subsequent contrasts showed statistically significant differences among treatment groups. ARI scores indicated the majority of adhesive remained on the bracket for all four groups. Pre-etching the bonding surface for 5 seconds with 37 per cent phosphoric acid, instead of pumicing, when using SEPs to bond orthodontic brackets, resulted in greater SBSs

    Statistical Reliability Estimation of Microprocessor-Based Systems

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    What is the probability that the execution state of a given microprocessor running a given application is correct, in a certain working environment with a given soft-error rate? Trying to answer this question using fault injection can be very expensive and time consuming. This paper proposes the baseline for a new methodology, based on microprocessor error probability profiling, that aims at estimating fault injection results without the need of a typical fault injection setup. The proposed methodology is based on two main ideas: a one-time fault-injection analysis of the microprocessor architecture to characterize the probability of successful execution of each of its instructions in presence of a soft-error, and a static and very fast analysis of the control and data flow of the target software application to compute its probability of success. The presented work goes beyond the dependability evaluation problem; it also has the potential to become the backbone for new tools able to help engineers to choose the best hardware and software architecture to structurally maximize the probability of a correct execution of the target softwar
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