A systematic review and meta-analysis of the survival of non-feldspathic porcelain veneers over 5 and 10 years

PURPOSE: This systematic review aimed to report and explore the survival of dental veneers constructed from non-feldspathic porcelain over 5 and 10 years.

MATERIALS AND METHODS: A total of 4,294 articles were identified through a systematic search involving all databases in the Cochrane Library, MEDLINE (OVID), EMBASE, Web of Knowledge, specific journals (hand-search), conference proceedings, clinical trials registers, and collegiate contacts. Articles, abstracts, and gray literature were sought by two independent researchers. There were no language limitations. One hundred sixteen studies were identified for full-text assessment, with 10 included in the analysis (5 qualitative, 5 quantitative). Study characteristics and survival (Kaplan-Meier estimated cumulative survival and 95% confidence interval [CI]) were extracted or recalculated. A failed veneer was one which required an intervention that disrupted the original marginal integrity, had been partially or completely lost, or had lost retention more than twice. A meta-analysis and sensitivity analysis of Empress veneers was completed, with an assessment of statistical heterogeneity and publication bias. Clinical heterogeneity was explored for results of all veneering materials from included studies.

RESULTS: Within the 10 studies, veneers were fabricated with IPS Empress, IPS Empress 2, Cerinate, and Cerec computer-aided design/computer-assisted manufacture (CAD/CAM) materials VITA Mark I, VITA Mark II, Ivoclar ProCad. The meta-analysis showed the pooled estimate for Empress veneers to be 92.4% (95% CI: 89.8% to 95.0%) for 5-year survival and 66% to 94% (95% CI: 55% to 99%) for 10 years. Data regarding other non-feldspathic porcelain materials were lacking, with only a single study each reporting outcomes for Empress 2, Cerinate, and various Cerec porcelains over 5 years. The sensitivity analysis showed data from one study had an influencing and stabilizing effect on the 5-year pooled estimate.

CONCLUSION: The long-term outcome (> 5 years) of non-feldspathic porcelain veneers is sparsely reported in the literature. This systematic review indicates that the 5-year cumulative estimated survival for etchable non-feldspathic porcelain veneers is over 90%. Outcomes may prove clinically acceptable with time, but evidence remains lacking and the use of these materials for veneers remains experimental.

Comparison of Composite Placement Techniques by Recently Qualified Dental Practitioners.

Objectives: To evaluate the placement of composite materials by new graduates using three alternative placement techniques.Methods: A cohort of 34 recently qualified graduates were asked to restore class II interproximal cavities in plastic teeth using three different techniques.

(i) A conventional incremental filling technique (Herculite XRV) using increments no larger than 2-mm with an initial layer on the cervical floor of the box of 1-mm.
(ii) Flowable bulk fill technique (Dentsply SDR) bulk fill placement in a 3-mm layer followed by an incremental fill of a microhybrid resin
(iii) Bulk fill (Kerr Sonicfill) which involved restorations placed in a 5-mm layer.

The operators were instructed in each technique, didactically and with a hands-on demonstration, prior to restoration placement.
All restorations were cured according to manufacturer’s recommendations. Each participant restored 3 teeth, 1 tooth per treatment technique.
The restorations were evaluated using modified USPHS criteria to assess both the marginal adaptation and the surface texture of the restorations. Blind evaluations were carried out independently by two examiners with the aid of magnification (loupes X2.5). Examiners were standardized prior to evaluation.
Results: Gaps between the tooth margins and the restoration or between the layers of the restoration were found in 13 of Group (i), 3 of Group (ii), and 4 of Group (iii)
Statistical analysis revealed a significant difference between the incrementally filled group (i) and the flowable bulk-fill group (ii) (p=0.0043) and between the incrementally filled (i) and the bulk fill groups (iii) (p=0.012) and no statistical difference (p=0.69) between the bulk filled groups Conclusions: Bulk fill techniques may result in a more satisfactory seal of the cavity margins when restoring with composite.

The direction aftereffect is driven by adaptation of local motion detectors

The processing of motion information by the visual system can be decomposed into two general stages; point-by-point local motion extraction, followed by global motion extraction through the pooling of the local motion signals. The direction aftereVect (DAE) is a well known phenomenon in which prior adaptation to a unidirectional moving pattern results in an exaggerated perceived direction diVerence between the adapted direction and a subsequently viewed stimulus moving in a diVerent direction. The experiments in this paper sought to identify where the adaptation underlying the DAE occurs within the motion processing hierarchy. We found that the DAE exhibits interocular transfer, thus demonstrating that the underlying adapted neural mechanisms are binocularly driven and must, therefore, reside in the visual cortex. The remaining experiments measured the speed tuning of the DAE, and used the derived function to test a number of local and global models of the phenomenon. Our data provide compelling evidence that the DAE is driven by the adaptation of motion-sensitive neurons at the local-processing stage of motion encoding. This is in contrast to earlier research showing that direction repulsion, which can be viewed as a simultaneous presentation counterpart to the DAE, is a global motion process. This leads us to conclude that the DAE and direction repulsion reflect interactions between motion-sensitive neural mechanisms at different levels of the motion-processing hierarchy.

Ethnic Nationalism and Adaptation in Cyprus

Both ethnic communities in Cyprus have maintained strong political and cultural ties with Greece and Turkey, respectively, and at some point of their twentieth century history, each has aspired to become part of either the former or the latter. Yet the way this relationship has been imagined has differed across time, space, and class. Both communities have adapted their identities to prevailing ideological waves as well as political opportunities, domestic alliances, and interests. The article evaluates different responses to ethnic nationalism, highlighting important intra-ethnic differentiations within each Cypriot community usually expressed in the positions of political parties, intellectuals, and the press. While the current literature identifies two major poles of identity in the island, "motherland nationalism" and "Cypriotism," the article suggests that the major focus of identity of Cypriots is identification with their respective ethnic communities in the form of Greek Cypriotism or Turkish Cypriotism. In fact, contentious politics in Cyprus from the ENOSIS/TAKSIM struggle to the April 2004 referendum demonstrate the interplay of external constraints and collective self-identification processes leading to the formation of these identities. The article concludes by identifying the implications of identity shifts for deeply divided societies and conflict resolution in general.

Habitat-specific adaptation of immune responses of stickleback (Gasterosteus aculeatus) lake and river ecotypes

Freshwater populations of three-spined sticklebacks (Gasterosteus aculeatus) in northern Germany are found as distinct lake and river ecotypes. Adaptation to habitat-specific parasites might influence immune capabilities of stickleback ecotypes. Here, naive laboratory-bred sticklebacks from lake and river populations were exposed reciprocally to parasite environments in a lake and a river habitat. Sticklebacks exposed to lake conditions were infected with higher numbers of parasite species when compared with the river. River sticklebacks in the lake had higher parasite loads than lake sticklebacks in the same habitat. Respiratory burst, granulocyte counts and lymphocyte proliferation of head kidney leucocytes were increased in river sticklebacks exposed to lake when compared with river conditions. Although river sticklebacks exposed to lake conditions showed elevated activation of their immune system, parasites could not be diminished as effectively as by lake sticklebacks in their native habitat. River sticklebacks seem to have reduced their immune-competence potential due to lower parasite diversity in rivers

The efficacy of colour cues in facilitating adaptation to opposing visuomotor rotations

We investigated visuomotor adaptation using an isometric, target-acquisition task. Following trials with no rotation, two participant groups were exposed to a random sequence of 30 degrees clockwise (CW) and 60 degrees counter-clockwise (CCW) rotations, with (DUAL-CUE), or without (DUAL-NO CUE), colour cues that enabled each environment (non-rotated, 30 degrees CW and 60 degrees CCW) to be identified. A further three groups experienced only 30 degrees CW trials or only 60 degrees CCW trials (SINGLE rotation groups) in which each visuomotor mapping was again associated with a colour cue. During training, all SINGLE groups reduced angular deviations of the cursor path during the initial portion of the movements, indicating feedforward adaptation. Consistent with the view that the adaptation occurred automatically via recalibration of the visuomotor mapping (Krakauer et al. 1999), post-training aftereffects were observed, despite colour cues that indicated that no rotation was present. For the DUAL-CUE group, angular deviations decreased with training in the 60 degrees trials, but were unchanged in the 30 degrees trials, while for the DUAL-NO CUE group angular deviations decreased for the 60 degrees CW trials but increased for the 30 degrees CW trials. These results suggest that in a dual adaptation paradigm a colour cue can permit delineation of the two environments, with a subsequent change in behaviour resulting in improved performance in at least one of these environments. Increased reaction times within the training block, together with the absence of aftereffects in the post-training period for the DUAL-CUE group suggest an explicit cue-dependent strategy was used in an attempt to compensate for the rotations.