Accuracy of torque controllers on healing abutments in implant dentistry-an in vitro study.

PURPOSE: To evaluate the accuracy of three torque-control devices used on healing abutments in implant prosthodontics. MATERIALS AND METHODS: In this in vitro experiment, three torque controllers, Ankylos friction-based, Straumann spring-based, and Anthogyr pre-calibrated torque control devices were used to tighten the healing abutments of Ankylos and Straumann dental implants to a pre-determined value of 15 Ncm. A digital torque meter (DT), Cedar DID-4A, was used to assess removal torque as a surrogate for the accuracy of the torque controllers to apply a tightening force of 15 Ncm on healing abutments.  One-way analysis of variance (ANOVA) was used to identify differences between each torque controller and the digital torquemeter, a p < 0.05 was considered significant. RESULTS: The torque required to remove the healing abutments was 16.05 ± 0.66 Ncm for the Ankylos ratchet, 12.61 ± 0.90 Ncm for the Straumann ratchet, and 14.37 ± 1.08 Ncm for the Anthogyr torque-control device. Significant statistical differences were observed between Ankylos and the control digital torquemeter (p = 1.84E-8 ; F = 50.3); Anthogyr and control digital torquemeter (p = 0.01; F = 6.79); and Straumann and control digital torquemeter (p = 0.01; F = 141.15). CONCLUSION: Friction-based (Ankylos), spring-based (Straumann), and pre-calibrated (Anthogyr) torque control devices present over-torque and under-torque values when used over healing abutments of Ankylos and Straumann implant systems.

Complement Factor I Gene Variant as a Treatable Cause of Recurrent Aseptic Neutrophilic Meningitis: A Case Report.

Mutations in the complement factor I (CFI) gene have previously been identified as causes of recurrent CNS inflammation. We present a case of a 26-year-old man with 18 episodes of recurrent meningitis, who had a variant in CFI(c.859G>A,p.Gly287Arg) not previously associated with neurologic manifestations. He achieved remission with canakinumab, a human monoclonal antibody targeted at interleukin-1 beta.

Implant and prosthetic rehabilitation of a patient with mucous membrane pemphigoid.

Mucous membrane pemphigoid (MMP) is an autoimmune condition characterized by subepithelial separation and deposition of autoantibodies and complement along the basement membrane zone. The disease results in the development of vesiculobullous lesions of the mucous membranes and skin. This report discusses the surgical treatment and management and the prosthetic implant rehabilitation of a patient with mucous membrane pemphigoid. The rationale for this treatment was to fabricate a prosthesis that was stable and did not rub against the gingival tissues and that was easily cleaned. The overdenture attachment system used provides more stability than other attachment systems while allowing the prosthesis and abutments to be easily cleaned.

On the Generalization of Simple Alternating Category Structures.

A fundamental question in the study of human cognition is how people learn to predict the category membership of an example from its properties. Leading approaches account for a wide range of data in terms of comparison to stored examples, abstractions capturing statistical regularities, or logical rules. Across three experiments, participants learned a category structure in a low-dimension, continuous-valued space consisting of regularly alternating regions of class membership (A B A B). The dependent measure was generalization performance for novel items outside the range of the training space. Human learners often extended the alternation pattern--a finding of critical interest given that leading theories of categorization based on similarity or dimensional rules fail to predict this behavior. In addition, we provide novel theoretical interpretations of the observed phenomenon.

Object understanding: Investigating the path from percept to meaning.

Researchers tend to follow two paths when investigating categorization: 1) artificial classification learning tasks and 2) studies of natural conceptual organization involving reasoning from prior category knowledge. Largely separate, another body of research addresses the process of object recognition, i.e., how people identify what they are looking at strictly in terms of visual as opposed to semantic properties. The present work brings together elements from each of these approaches in order to address object understanding: the ubiquitous natural process of accessing meaning based on a realistic image of an everyday object. According to a widely held features-first framework, a stimulus is initially encoded as a set of features that is compared to stored category representations to find the best match. This approach has been successful for explaining artificial classification learning, but it bypasses how items are encoded and fails to include a role for top-down processing in constructing item representations. We used a speeded verification task to evaluate the features-first account using realistic stimuli. Participants saw photographic images of everyday objects and judged as quickly as possible whether a provided verbal description matched the picture. Category descriptions (basic-level labels) were verified significantly faster than descriptions of physical or functional properties. This suggests that people access the category of the stimulus prior to accessing its parsed features. We outline a construal account whereby the category is accessed first to construct a featural item interpretation rather than features being the basis for determining the category.

Preventing inert knowledge: Category status promotes spontaneous structure-based retrieval of prior knowledge.

Analogical comparison of 2 provided cases promotes spontaneous analogical transfer by encouraging a more abstract representation of a target principle. This is widely understood as a process of schema abstraction that aids retrieval from memory in the absence of superficial similarity. The category status hypothesis states that if knowledge about a target principle is represented as a relational category, it is easier to activate as a result of categorizing (as opposed to cue-based reminding). To investigate these 2 pathways to spontaneous transfer (schema retrieval vs. categorization), participants were assigned to different study conditions: (a) standard comparison of 2 analogs; (b) standard comparison followed by a second comparison of 2 new analogs; or (c) a guided Category-building task based on a foundation of sequential summarization with additional categorization supports. Experiment 1 showed improved spontaneous transfer in the Category-building task relative to Single-comparison-the gold standard for encouraging spontaneous transfer. Experiment 2 demonstrated that the Category-building task led to more frequent spontaneous structure-based retrieval than either comparison-based task. This suggests that the transfer improvements observed in Experiment 1 are attributable to the Category-building task making superficially dissimilar prior knowledge more accessible. Experiments 3a and 3b tested alternative explanations of this finding and provided evidence that the effectiveness of the Category-building task arises from encouraging the construal of a target principle as a relational category. These findings support categorization as a critical factor in explaining successful spontaneous analogical retrieval and toward instructional approaches that promote portable rather than inert knowledge. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Dentist-laboratory communication and quality assessment of removable prostheses in Oregon: A cross-sectional pilot study.

STATEMENT OF PROBLEM: When fabricating a removable dental prosthesis, it is unclear if the information received by the dental laboratory technician is clear and sufficient. PURPOSE: The purpose of this survey study was to evaluate the dentist's work authorizations for removable prostheses as well as determine common practices used by laboratories during the fabrication of removable prostheses. MATERIAL AND METHODS: A 24-item questionnaire was developed based on previously published questionnaires and incorporating new topics. A public uniform resource locator (URL) survey link was generated and sent to the office of the Oregon Association of Dental Laboratories (OADL). The executive director of the board then sent out the link to 163 participants that included members and nonmembers of the OADL who were still active in the state of Oregon. Two reminder e-mails were sent 2 weeks apart. Study data were collected and managed by using the Research Electronic Data Capture (REDCap) software program. Descriptive statistics were tabulated, and responses displayed as a percentage of the total. RESULTS: From the 163 invited participants, 26 responded to the survey representing a 15.9% response rate. Only 11% of the laboratories stated that they routinely receive work authorizations with clear instructions. All participants stated that they always (62.5%) or frequently (37.5%) design the partial prostheses frameworks. Only 37.5% of the laboratories stated that they usually receive adequately extended and accurate definitive casts to fabricate the framework. Fifty percent of the laboratories stated that they very rarely perform altered cast procedures and 50% indicated that half or more of the removable partial prostheses they fabricate were entirely made of acrylic resin. Most laboratories stated that thermoplastic resin partial dentures were less than 25% of their produced volume of removable prostheses. Only 22% of respondents stated that they usually receive adequate information to complete a denture tooth arrangement and most (78%) dentists do not routinely specify the type of occlusal scheme desired for their complete denture tooth arrangements. In most prostheses (77%), posterior palatal seal was marked by the prescribing dentists rarely or very rarely. CONCLUSIONS: Work authorizations provided by the dentists were less than adequate and left much decision-making to the dental laboratory technician.

Similarity judgments predict N400 amplitude differences between taxonomic category members and thematic associates.

Human similarity judgments do not reliably conform to the predictions of leading theories of psychological similarity. Evidence from the triad similarity judgment task shows that people often identify thematic associates like dog and bone as more similar than taxonomic category members like dog and cat, even though thematic associates lack the type of featural or relational similarity that is foundational to theories of psychological similarity. This specific failure to predict human behavior has been addressed as a consequence of education and other individual differences, an artifact of the triad similarity judgment paradigm, or a shortcoming in psychological accounts of similarity. We investigated the judged similarity of semantically-related concepts (taxonomic category members and thematic associates) as it relates to other task-independent measures of semantic knowledge and access. Participants were assessed on reading and language ability, then event-related potentials (ERPs) were collected during a passive, sequential word reading task that presented pseudowords and taxonomically-related, thematically-related, and unrelated word sequences, and, finally, similarity judgments were collected with the classic two-alternative forced-choice triad task. The results uncovered a correspondence between ERP amplitude and triad-based similarity judgments-similarity judgment behavior reliably predicts ERP amplitude during passive word reading, absent of any instruction to consider similarity. It was also found that individual differences in reading and language ability independently predicted ERP amplitude. This evidence suggests that similarity judgments are driven by reliable patterns of thought that are not solely rooted in the interpretation of task goals or reading and language ability.

Comparison-based learning of relational categories (you'll never guess).

In accord with structural alignment theory, same-category comparison opportunities within a classification learning task should promote relational category acquisition. However, a straightforward merging of the classification paradigm with copresentation of same-category item pairs does not yield an advantage relative to an equal number of single-item exposures. In 3 experiments, we explore the hypothesis that the traditional classification learning mode (guess-and-correct) and comparison have a previously unforeseen incompatibility. In Experiment 1, we test this hypothesis by contrasting classification with supervised observational learning (passive study of labeled examples) under 3 presentation formats: same-category pairs, mixed pairs, and single-item. We find an observational advantage with same-category pairs and produce the elusive advantage over single-item exposures. In Experiment 2, we assess the generality of the learning mode effect by testing both same- and different-category comparison. The observational advantage replicates and extends to different-category comparison-although, we do not find a significant difference between the 2 types of comparison. In Experiment 3, relative to the classification mode, we find enhanced performance in an intermediate learning mode between classification and observation in which participants are instructed to make a covert category guess (without making an actual response) before seeing the correct category label. Implications and interpretations-including our interpretation that the performance emphasis inherent in classification learning undermines the benefits that arise from comparison opportunities-are discussed. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Revisiting the linear separability constraint: New implications for theories of human category learning.

While the ability to acquire non-linearly separable (NLS) classifications is well documented in the study of human category learning, the relative ease of learning compared to a linear separable structure is difficult to evaluate without potential confounds. Medin and Schwanenflugel (Journal of Experimental Psychology: Human Learning and Memory, 7, 355-368, 1981) were the first to demonstrate that NLS classifications are not more difficult to acquire than linearly separable ones when structures are equated in terms of within- and between-category similarities. However, their evidence is less sturdy than might be expected due to non-standard methodology and low sample size. We conducted a conceptual replication to clarify the behavioral picture and perform qualitative testing of formal models. The behavioral results not only showed a lack of advantage for the linearly separable (LS) structure, but revealed a stronger finding: the NLS structure was reliably easier to acquire. Differences in the relative ease of NLS learners to master certain items yielded evidence for the existence of distinct learner subgroups, one marked by significantly easier (not harder) learning of exception items. Comparing the qualitative fits of leading computational models to the human learning performance confirmed that a pure prototype account, even with contemporary updates, remains incompatible with the data. However, exemplar models and similarity-based models grounded in sophisticated forms of abstraction-based learning successfully account for the NLS advantage. In sum, evidence against a linear separability constraint is redoubled, and the observed NLS advantage along with behavioral patterns seen at the subgroup and item level provide a valuable basis for comprehensive evaluation of competing theoretical accounts and models.

Sorting out the problem of inert knowledge: Category construction to promote spontaneous transfer.

A fundamental goal in the study of human cognition is to understand the transfer of knowledge. This goes hand-in-hand with the translational goal of promoting such transfer via instructional techniques. Despite a rich history of research using the analogical problem-solving paradigm, no study activity has been found to produce a robust rate of successful spontaneous transfer-even when the test is immediate. We propose the category status hypothesis as an explanation of the difficulty of transfer and as motivation for a novel approach to promoting transfer. We report a set of experiments evaluating a category construction technique based on a sorting task. In Experiment 1a, we found category construction to be significantly more effective than the "gold standard" of schema abstraction through comparison of 2 analogous cases. In Experiment 1b, we explored a variation of the category construction technique that did not reliably differ in effectiveness from comparison-based schema abstraction-we also verified that both study tasks were superior to a baseline task of separate summarization of 2 cases. In Experiment 2, we conducted a replication of the initial design with higher power and confirmed the significant advantage for category construction over schema abstraction via comparison. In Experiment 3, we compared category construction to an information-consistent reading comprehension control to evaluate competing interpretations of the category construction advantage found in Experiments 1 and 2. We discuss theoretical and applied implications of these findings. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The use of 3D printing in shared decision making for a juvenile aggressive ossifying fibroma in a pediatric patient.

Juvenile aggressive ossifying fibromas (JAOF) are rare, typically benign pediatric tumors that are locally aggressive and have high recurrence rates. A 7-year old male presented with a palatal mass and a 3D printed model was created and used as a visual aide to highlight the importance of management in terms of functional, cosmetic, and disease-free outcomes with the family. The patient ultimately underwent successful enucleation with final pathology consistent with JAOF. To our knowledge, this is the first description of the use of 3D printing to help in the shared decision-making process for the treatment of this aggressive tumor.

Evidence of analogical re-representation from a change detection task.

The flexibility to map similar, but non-identical relations, is a key characteristic of human analogical reasoning. Understanding how this flexibility is implemented is necessary for a complete accounting of analogical processes. The structure mapping theory of analogy addresses this issue by invoking re-representation-an online transformation of conceptually similar relational content that reveals potential partial identity matches between predicates. Despite the critical importance of re-representation to structure mapping, very little empirical work has validated the psychological reality of this mechanism, with the existing evidence being no more than suggestive. The present work investigates the likelihood of re-representation across two experiments using a novel change detection task. The resultant findings demonstrate precise evidence of representational change in relational content of analogs. Experiment 2 further explores the relationship between lower-order relational similarity and the likelihood of re-representation.

Similarity is as similarity does? A critical inquiry into the effect of thematic association on similarity.

Leading theories of psychological similarity are based on the degree of match in semantic content between compared cases (i.e., shared features, low dimensional distance, alignable relations). Broader forms of semantic relatedness such as the degree of association between cases (e.g., egg and spatula) are generally not considered to contribute to similarity judgments. However, empirical work has demonstrated a behavioral tendency to choose associated pairs over proximal pairs (i.e., high semantic content overlap) in similarity judgement tasks. As a result, models have been proposed that combine thematic integration and content match as component processes of similarity. The present experiments investigate the thematic association effect in similarity in order to more clearly determine whether such a theoretical redirection is warranted. An alternative viewpoint is that confusion between similarity and association is the cause of the reported thematic bias. Experiment 1 introduces a modified similarity judgement task and addresses the impact of task instructions as a potential causal factor underlying the thematic association effect on similarity. Experiment 2 specifically compares the novel similarity task to a traditional two-alternative, forced choice triad task. Experiment 3 addresses the possibility of bias in the stimulus sets used in Experiments 1 and 2. Across the experiments we find association-based responding to be much less prevalent than in previous demonstrations: the traditional finding of a thematic preference only occurred when participants were specifically asked to select based on associativity ("goes with"). Modifications to conventional methodology that minimize biasing factors clearly attenuate the effect of association on similarity. We interpret these findings as evidence that that the thematic association effect derives from intrusions on psychological similarity, not from an additional component intrinsic to psychological similarity.

Analogies Without Commonalities? Evidence of Re-representation via Relational Category Activation.

Analogies between cases with matching sets of connected relational structure is well-explained by existing theory. Re-representation is posited as an important mechanism to increase the flexibility of analogical processing by allowing the alignment of non-identical predicates across compared cases. It has been proposed that certain kind of categories can be characterized in terms of the relational structure that its exemplars tend to satisfy. Such relational categories have the property that all members of the category are analogous to one another. We ask whether a process of re-representation can alter the construal of a case and bring two evidently non-analogous cases into analogical alignment if they are both seen as members of the same relational category. We examine analogies between pairs of cases where the base is a canonical example of a relational category and the target would not be considered a member of the category on its own - critically, the cases themselves share no evident relational identities or similarities. In Experiment 1, we ask whether presenting a target case as part of an analogical pairing alters its construal. In Experiment 2, the pairs are presented for judgment as potential analogies. In both studies, participants interpret the target cases differently (consistent with the relational category) as a result of processing the analogy. There are two main implications: (1) a form of re-representation is at work in which the activation of a relational category triggers an alternate construal of the target case; and (2) this suggests a path to analogical status for cases that lack relational identities or similarities if the cases can both be fit to the same relational category.

Shark Fin Titanium Hollow Bulb Obturator: A Treatment Concept.

Restoring esthetics and function for patients with maxillectomy defects presents a complex challenge for the clinician. Obturator prostheses are subject to rotational forces during function, allowing movement into the defect. Gaining prosthesis support from endosseous implants can limit the amount of rotation. Xerostomia and impaired tissue healing caused by radiation therapy further complicates the treatment for such patients. Several resilient and rigid obturator design concepts are available for restoration of such defects. This clinical report describes a design concept used to treat a patient with a maxillectomy defect caused by tumor resection secondary to a squamous cell carcinoma.

Learning relational concepts from within- versus between-category comparisons.

This article examines relational category learning in light of 2 influential theories of concept acquisition: the structure-mapping theory of analogy and theories of feature-based category learning. According to current theories of analogy, comparing 2 instances of a relational concept enables alignment of their elements and reveals their shared relational structure. Therefore, learning relationally defined categories should be faster when comparing items of the same category than when comparing items of different categories. By contrast, feature-based theories predict a benefit of between-category comparisons, because such comparisons direct attention to the features that discriminate the categories. The present experiments tested these predictions using a 2-category classification-learning task in which 2 items are presented on every trial: either in the same category (match condition) or in different categories (contrast condition). Subjects in the contrast condition outperformed those in the match condition for feature-based categories (Experiment 1) and across 4 different types of relational categories (Experiments 1-4). Although theorists have posited that structure-mapping theory is directly applicable to relational category learning, the present findings pose a distinct challenge to this assertion. We propose that many relational categories are learnable based solely on which relations are present in the stimulus rather than requiring explicitly compositional representations based on role-filler binding. This process would be akin to feature processing and would not require structural alignment. This theoretical proposal, together with the empirical results, may lead to a better understanding of when people do and do not engage in the cognitively demanding process of structural alignment. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Digital Relief of the Mental Foramen for a CAD/CAM-Fabricated Mandibular Denture.

Relief of the intaglio surface of a denture base is conventionally performed using thin wax and soft metal foil attached to the master cast. The following report highlights a new relief procedure for the mental foramen using a CT double scan technique on the CAD/CAM dentures fabricated for the patient with paresthesia of the left lower lip and chin during mastication.

An In Vitro Investigation of Veneered Zirconia-Based Restorations Shade Reproducibility.

PURPOSE: To examine the effects of the veneering technique on the shade reproducibility of zirconia-based crowns. MATERIALS AND METHODS: An artificial tooth was prepared with a 1.2 mm heavy chamfer finish line and 8° taper. The prepared tooth was scanned using CAD/CAM technology to fabricate 45 cobalt chromium (CoCr) testing dies. One CoCr die was scanned, and 45 zirconia copings were milled and devided according to the veneering technique into 3 groups of 15 specimens each: layering veneering (LV) using Vita Vm9, overpressing veneering (OV) using Vita Pm9, and digital veneering (DV) using Vita Triluxe forte. All veneering layers had the same shade (A2). The specimens were cemented onto the testing dies using glass inomer cement. A spectrophotometer was used to measure the shade coordinates (L, C, h, a, b) for a Vita A2 shade tab and for each specimen. Both the CIE Lab (ΔEab ) and the CIE DE2000 (ΔE00 ) color difference formulas were applied to compare the shade tab and the study groups. One-way ANOVA and multiple comparison Bonferroni tests were applied for statistical analysis of the results. RESULTS: Means and standard deviations (SDs) of ΔEab were 2.3 ± 1.3 for LV, 3.5 ± 0.8 for OV, and 4.0 ± 0.7 for DV. Means and SDs of ΔE00 were 1.4 ± 0.8 for LV, 2.1 ± 0.5 for OV, and 3.1 ± 0.4 for DV. ΔEab of LV group was significantly lower (p < 0.05) than both OV and DV groups, whereas the difference in ΔEab between OV and DV groups was not significant (p = 0.39). The differences in ΔE00 between all groups were significant (p < 0.05). CONCLUSIONS: LV group was superior to other groups in terms of shade reproducibility. The ΔEab and the ΔE00 values of LV and OV groups were within clinically acceptable ranges; however, the ΔEab and the ΔE00 values of group DV were beyond the clinically acceptable ranges. The ΔE00 formula demonstrated a statistically significant difference between OV and the DV groups, while the ΔEab formula did not. The zirconia veneering technique had a significant influence on the shade reproducibility of zirconia-based crowns.

Veneered Zirconia-Based Restorations Fracture Resistance Analysis.

PURPOSE: To examine the effects of the veneering technique on the fracture resistance of zirconia-based crowns. MATERIALS AND METHODS: An artificial tooth was prepared with a 1.2 mm heavy chamfer finish line and 8° taper. The prepared tooth was scanned using CAD/CAM technology to fabricate 45 cobalt chromium (CoCr) testing dies. One CoCr die was scanned, and 45 zirconia copings were milled and divided according to the veneering technique into three groups of 15 specimens each: layering veneering (LV) using Vita Vm9, overpressing veneering (OV) using Vita Pm9, and digital veneering (DV) using Vita Triluxe forte. The crowns were cemented onto the testing dies using glass ionomer cement. The specimens were thermocycled (3000 cycles, 5° to 55°) then statically loaded (3.7 mm ball, 0.5 mm/min crosshead speed) until failure. Failed crowns were inspected using a magnifier, and failure patterns were identified. One-way ANOVA and multiple comparison Bonferroni tests were applied for statistical analysis of the results. RESULTS: Means and standard deviations of failure loads were 1200 ± 306 N for the LV group, 857 ± 188 N for the OV group, and 638 ± 194 N for the DV group. The differences in failure loads were statistically significant between all groups (p < 0.05). Failure mode was predominantly cohesive for LV and OV groups, whereas it was predominantly adhesive for the DV group. CONCLUSIONS: The LV group was superior to other groups in terms of fracture resistance, while the DV group was inferior to the other groups in the same aspect.