The predictability of maxillary curve of Spee leveling with the Invisalign appliance.

OBJECTIVES: To evaluate the predictability of the Invisalign appliance (Align Technology, Santa Clara, Calif) in leveling the maxillary curve of Spee (COS). MATERIALS AND METHODS: A retrospective sample of adult subjects treated with the Invisalign appliance between 2013 and 2019 were selected. Patients were treated nonextraction in the maxillary arch and had either Angle Class I or II malocclusions with a minimum of 14 aligners with no bite ramps. Initial, predicted, and actual outcomes were analyzed with Geomagic Control X software (version 2017.0.3; 3D Systems, Cary, NC). RESULTS: A sample of 53 cases satisfied inclusion/exclusion criteria. Paired t-tests demonstrated a significant difference between mean predicted and actual maxillary COS leveling with a shortfall of 0.11 mm (SD = 0.37; P = .033). Planned intrusion tended to be more accurate posteriorly with an overexpression of 117% for the first molars. Planned extrusion was the least accurate, with the mid-arch demonstrating expressions of -14% to -48%. These teeth intruded despite a prescribed extrusive movement. CONCLUSIONS: The Invisalign appliance did not accurately predict maxillary COS leveling. Planned intrusive movements were overcorrected, and planned extrusive movements were either undercorrected or resulted in intrusion. This effect was most apparent for the upper first molar, which expressed 117% and -48% of planned intrusion and extrusion, respectively.

The predictability of maxillary curve of Wilson leveling with the Invisalign appliance.

BACKGROUND: This retrospective study aims to evaluate the predictability of the Invisalign appliance (Align Technology, Santa Clara, CA) in leveling the maxillary curve of Wilson (COW). METHODS: 53 adult subjects treated by orthodontists who are experienced Invisalign providers, between 2013 and 2019 were selected. All patients had either Angle Class I or II malocclusions and were treated by non-extraction in the maxillary arch with a minimum of 14 Invisalign aligners with no bite ramps or auxiliaries. Initial, predicted, and actual outcomes were analyzed with Geomagic Control X software (3D systems, Rock Hill, SC; Version 2017.0.3). RESULTS: Despite planning mean (SD) COW leveling of 0.25 mm (1.91), the curve became significantly more pronounced by 1.15 mm (0.85) (P < .001). There was a significant overexpression of buccal inclinations between mean prescribed versus actual values from 0.10 mm (0.39) (P = .007) to 0.29 mm (0.47) (P < .001) from the first premolars to the second molars, respectively. These differences were more pronounced posteriorly. The differences between the predicted and actual arch width values were underexpressed for all teeth except the second molars; a mean underexpression between 0.28 mm (0.92) and 0.60 mm (1.14). The second molars were the only teeth to overexpress with a mean of 0.42 mm (1.02). CONCLUSIONS: Overall mean maxillary COW was not predictably controlled with Invisalign. The appliance tends to overexpress the buccal crown tip regardless of prescribed direction, especially posteriorly. Arch expansion was underexpressed at all levels of the arch except for second molars which overexpressed by almost four times.

Population dynamics and growth rates of free-living mushroom corals (Scleractinia: Fungiidae) in the sediment-stressed reefs of Singapore.

The reefs of Singapore provide an excellent opportunity to study the population dynamics and growth rates of free-living mushroom corals (Fungiidae) under sediment-stressed conditions. Transect surveys at four study sites revealed a total of 11 free-living mushroom coral species-the same 11 species as those found by local studies since the 1980s. The abundance of the four most common species ranged from 1.0 to 68.3 Ind. per 100m2, while their population size-structure showed a common pattern of a higher proportion of small-sized corals than large-sized ones (i.e. positively skewed size-structure), although very few individuals of the smallest-size classes were recorded for any of the four species. A more positively skewed size-structure for each of the four most common species was observed at the reef slope (5-6m depth) than at the reef crest (2-3m depth), possibly due to a slower growth rate caused by light reduction with depth. All the mushroom corals studied exhibited a decline in growth rate with increasing size and weight, indicating determinate growth. Growth rate of each of the four most common species was similar among the study sites, despite variation in environmental conditions. Our results demonstrate species richness stability over the past three decades, suggesting that these free-living mushroom coral assemblages comprise species that are well-adapted to the chronic high sedimentation characteristic of Singapore's reefs. However, if the paucity of individuals of the smallest-size classes reflects poor recruitment and/or early mortality, there may be some cause for concern. Our robust baseline data can contribute to a long-term monitoring strategy for determination of changes in mushroom coral population dynamics.

Artificially innervated self-healing foams as synthetic piezo-impedance sensor skins.

Human skin is a self-healing mechanosensory system that detects various mechanical contact forces efficiently through three-dimensional innervations. Here, we propose a biomimetic artificially innervated foam by embedding three-dimensional electrodes within a new low-modulus self-healing foam material. The foam material is synthesized from a one-step self-foaming process. By tuning the concentration of conductive metal particles in the foam at near-percolation, we demonstrate that it can operate as a piezo-impedance sensor in both piezoresistive and piezocapacitive sensing modes without the need for an encapsulation layer. The sensor is sensitive to an object's contact force directions as well as to human proximity. Moreover, the foam material self-heals autonomously with immediate function restoration despite mechanical damage. It further recovers from mechanical bifurcations with gentle heating (70 °C). We anticipate that this material will be useful as damage robust human-machine interfaces.

Allelopathic effects of macroalgae on Pocillopora acuta coral larvae.

Allelopathy has been proposed as a key mechanism mediating coral-algal interactions; however, few studies have tested macroalgal allelochemicals on coral larvae. In this study, we examined the effects of crude extracts from four macroalgal species on Pocillopora acuta larvae under different exposure conditions. Larval mortality increased considerably with increasing concentrations of Bryopsis sp., Endosiphonia horrida, and Lobophora sp. extracts. Increasing E. horrida and Lobophora sp. extract concentrations also substantially decreased larval settlement. No detectable effects on larvae were observed in Hypnea pannosa extracts. Further, while larval mortality increased with exposure duration to Lobophora sp. extracts, larval settlement was enhanced at 12 h exposure, but reduced at shorter and longer durations. Our results emphasize that macroalgal chemical effects are highly dependent on macroalgal species and exposure conditions. On reefs dominated by allelopathic macroalgae, the survivorship and settlement of coral larvae are potentially constrained, thereby limiting the recovery of degraded reefs.