Evaluation of mandibular growth in a prepubertal Class I and Class II population: a longitudinal analysis.

OBJECTIVE: This study aims to identify the presence, timing, and magnitude of a prepubertal mandibular growth spurt in a Class I and Class II population. METHODS: From the Burlington and Iowa Growth study of the AAOF Craniofacial Growth Legacy Collection, 83 Class I subjects (37 females and 46 males) and 32 Class II subjects (18 males and 14 females) were identified, as having at least seven consecutive annual lateral cephalograms taken from 5 to 11 years of age. Only subjects with a normodivergent facial pattern were considered. A customized cephalometric analysis was performed, and total mandibular length, defined as the distance between Condylion (Co) and Gnathion (Gn), was calculated. RESULTS: Overall, a significant early peak of mandibular growth was present in all the subjects analysed both in Class I (4.69 mm for males and 4.18 mm for females; P < .05) and in Class II (5.85 mm for males and 4.05 mm for females; P < .05). No differences between males and females were found for the timing of this peak (7 years for Class I and Class II females and 7 years for Class I and 6.5 years for Class II males). In males, a significantly larger peak was observed in Class II than Class I subjects (P = .007). LIMITATIONS: The main limitations of this study were the impossibility of using a suitable growth indicator to identify the timing of the early mandibular growth peak and the limited Class II records retrievable. CONCLUSION: This investigation suggests that a prepubertal mandibular growth peak is consistently present in both Class I and Class II males and females of clinically significant magnitude. Despite that, chronological age confirms to be unsuitable to identify this peak.

A systematic and comprehensive protocol for rapid orthodontic extrusion.

OBJECTIVE: The aim of the present paper is to describe a systematic and detailed protocol for rapid orthodontic extrusion, and to summarize the main results of this protocol in terms of migration of dental, hard and soft tissues, for 10 cases. CLINICAL CONSIDERATIONS: The working design was to apply a protocol lasting 4 weeks of active phase with intense forces (greater than 300 g), perform weekly the circumferential supra-crestal fiberotomy procedure associated with root-planning, follow up with a passive stabilization phase of another 4 weeks and evaluate the results. CONCLUSIONS: We believe that despite the partial migration of periodontal tissue, the defined protocol we used is, for simplicity of application, brevity of treatment and results, a viable alternative to the surgical technique of clinical crown lengthening in those cases where it is necessary to have more dental tissue exposed for restorative and prosthetic purposes.

Correlation of Shear Bond Strength and Degree of Conversion in Conventional and Self-Adhesive Systems Used in Orthodontic Bonding Procedures.

(1) Background: Self-adhesive systems have been proposed for the orthodontic bonding with the intention to reduce the traditional three-component system. (2) Methods: The sample consisted of 32 extracted intact permanent premolars randomly divided into two groups (n = 16). In Group I the metal brackets were bonded with Transbond XT Primer and Transbond XT Paste. In Group II the metal brackets were bonded with GC Ortho connect. The resin was polymerized for 20 s from two directions (mesial and occlusal) using a Bluephase light-curing unit. The shear bond strength (SBS) was measured using a universal testing machine. Immediately after SBS testing, Raman microspectrometry was performed for each sample to calculate the degree of conversion (DC). (3) Results: There was no statistically significant difference in the SBS between the two groups. A significantly higher DC (p < 0.001) value was recorded in Group II, in which the brackets were bonded with GC. Very weak or no correlation (0.01) was recorded between SBS and DC in Group I and moderate positive correlation was recorded in Group II (0.33). (4) Conclusions: No difference was found in SBS between the conventional and two-step systems used in orthodontics. The two-step system demonstrated higher DC compared to the conventional system. There is a very weak or moderate correlation between DC and SBS.

Odontostomatological Traits in North-Eastern Italy's Isolated Populations: An Epidemiological Cross-Sectional Study.

Malocclusions and temporomandibular disorders (TMDs) are oral health problems that are spread worldwide. To date, few studies focused on their prevalence and associated risk factors are available. This study aims to define the prevalence and distribution of odontostomatological traits and evaluate specific risk factors in isolated villages in north-eastern Italy, taking advantage of their environmental homogeneity. Nine hundred and forty-four participants aged six to eighty-nine years were enrolled. Thirty-one odontostomatological phenotypes, classified into five domains (airways, bad habits, extraoral and intraoral parameters, TMDs, and teeth), were evaluated. A descriptive statistical analysis was performed; mixed logistic models were used to test the relationships among the traits. According to the study's findings, Angle's class I was prevalent (65.3%) followed by class II malocclusion (24.3%); class III and reversed overjet were the least frequent malocclusions (10.4% and 1.8%, respectively). Temporomandibular joint (TMJ) click/noise was prevalent among TMDs (34.7%). The statistically significant (p-value < 0.05) risk factors were ankyloglossia for phonetic issues (OR 1.90) and bruxism for TMJ click/noise (OR 1.70) and pain (OR 2.20). Overall, this work provides a picture of the prevalence of malocclusions and TMDs in a large Italian sample and reveals risk factors to take into account in the development of preventive strategies and treatments.

Bone quality in relation to skeletal maturation in palatal miniscrews insertion sites.

INTRODUCTION: This study aimed to investigate the relationship between bone density and quantity at the insertion sites of palatal miniscrews and skeletal maturation-evaluated with the middle phalanx maturation method-in growing patients. METHODS: Sixty patients were analyzed as having a staged third finger middle phalanx radiograph and a cone-beam computed tomography of the maxilla. On the cone-beam computed tomography, a grid was designed to parallel the midpalatal suture (MPS) and posterior to the nasopalatine foramen, both on the palatal and lower nasal cortical bones. Bone density and thickness were measured at the intersections, and medullary bone density was also calculated. RESULTS: Of patients in MPS stages 1-3, 67.6% showed a mean palatal cortical thickness of <1 mm, whereas in 78.3% of the patients in stages 4 and 5, it was >1 mm. The nasal cortical thickness showed a similar trend (MPS stages 1-3: 62.16% <1 mm; MPS stages 4 and 5: 65.2% >1 mm). There was a significant difference in the density of the palatal cortical bone between MPS stages 1-3 (1272.05 ± 191.13) and stages 4 and 5 (1572.33 ± 274.89) and in nasal cortical density between MPS stages 1-3 (1428.09 ± 198.97) and stages 4 and 5 (1597.97 ± 267.75) (P <0.001). CONCLUSIONS: This study revealed a correlation between skeletal maturity and maxillary bone quality. MPS stages 1-3 have lower palatal cortical bone density and thickness but high nasal cortical bone density values. MPS stage 4 and, even more, stage 5 show increasing palatal cortical bone thickness and palatal and nasal cortical bone density values.

Duration of stages of the Middle Phalanx Maturation method in a contemporary population: A 6-year longitudinal analysis.

OBJECTIVE: To determine the duration and age at the beginning of each stage corresponding to the circumpubertal period in the Middle Phalanx Maturation method (MPM) and to assess the differences between males and females. MATERIALS AND METHODS: Sets of X-rays of the middle phalanx of the third finger taken at 6-month intervals were analysed for 246 skeletal Class I subjects (102 females and 144 males) between 9 and 15 years of age. After staging, the duration of each stage was derived from chronological ages, and the difference between males and females for both duration and age at the beginning of each stage was investigated. RESULTS: The median duration for MPS2 and MPS3 was 1 year for both sexes, while MPS4 showed a median duration of 1 year in females and 9 months in males, with no significant differences between the sexes. Mean age at the beginning of MPS2 was 10y11m for females and 11y11m for males; for MPS3, it was 11y8m for females and 13y1m for males; for MPS4, it was 12y9m for females and 13y11m for males; for MPS5, it was 13y4m for females and 14y3m for males. The differences between the sexes were statistically significant for all the stages (P < .001). CONCLUSIONS: This study confirms, with relevant sample size, the median duration of 1 year for each MPM stage from MPS2 to MPS4. Despite the distinctive interindividual variability, the interquartile range is 6 months or less for all but one interval, confirming the soundness of the results.

Does the planned miniscrew position reflect the achieved one? A clinical study on the reliability of guided miniscrew insertion using lateral cephalogram and maxillary stereolithography file for planning.

INTRODUCTION: The anterior area of the palate is widely used as an insertion site for orthodontic miniscrews. These temporary anchorage devices can be placed either directly or using an insertion guide, and various kinds of digital planning and guides are currently available. This study aimed to verify if the guided procedure can guarantee the correct position of the miniscrews on the patient compared with the digital project. METHODS: Twenty-five consecutively treated patients were included in the study. Angular and linear displacements of the miniscrews were evaluated among 3 groups: the planned position, the model position, and the achieved position. RESULTS: The median achieved angle between 2 digitally planned screws was 6.22° (interquartile range: 4.35°, 9.08°) and the difference between the angles in the planning and the achievement groups was significant (P <0.001). Lateral and vertical differences were also found among the 3 groups. CONCLUSIONS: Results show that the examined workflow is clinically efficient. Differences between the digitally planned position of the orthodontic miniscrews, the control position, and the achieved position were detected both for angular and linear measurements but were not clinically significant.

Accuracy of the digital workflow for guided insertion of orthodontic palatal TADs: a step-by-step 3D analysis.

BACKGROUND: The introduction in the orthodontic field of the digital workflow for guided insertion of palatal TADs and the development of the 1-visit protocol led to the reduction of chair time and the possibility of complete customization of designs and materials. Conversely, the reduction of operative steps implicates a lower tolerance of deviations between the planned and the actual position of the miniscrews, particularly when the orthodontic device is fixed on 4 palatal TADs or has a rigid structure. This study aims to analyze the influence of each step of the digital workflow on the deviation of the miniscrews' axis of insertion in a bicortical sample. The null hypothesis is that there are no significant differences in the deviations among the operative steps. METHODS: 33 subjects were selected for insertion of bicortical palatal miniscrews with a 1-visit protocol. Digital files were collected at the three stages of the workflow (i.e., digital planning, laboratory prototype, post-insertion impression). A 3D software analysis was performed on a total of 64 miniscrews. After automatic shape recognition of the guiding holes of the digital plan and the scanbodies of the laboratory prototype and post-insertion impression as geometric cylinders, their three-dimensional longitudinal axis was traced and the deviation among them was calculated. Friedman test with Bonferroni correction was performed to assess the significance of the deviations among the three steps, with significance set at p < 0.05. RESULTS: The laboratory step has a significantly lower degree of deviations (2.12° ± 1.62) than both the clinical step (6.23° ± 3.75) and the total deviations (5.70° ± 3.42). No significant differences were found between miniscrews inserted on the left or the right side. CONCLUSIONS: This study suggests that laboratory procedures such as surgical guide production or rapid prototyping don't play a significant role in the degree of deviations between the planned and the positioned palatal TADs. Conversely, the clinical steps have a bigger influence and need to be carefully evaluated. Despite this difference, there is a cumulative effect of deviations that can lead to the failure of the 1-visit protocol.

Motion-Capture Patterns of Voluntarily Mimicked Dynamic Facial Expressions in Children and Adolescents With and Without ASD.

Research shows that neurotypical individuals struggle to interpret the emotional facial expressions of people with Autism Spectrum Disorder (ASD). The current study uses motion-capture to objectively quantify differences between the movement patterns of emotional facial expressions of individuals with and without ASD. Participants volitionally mimicked emotional expressions while wearing facial markers. Recorded marker movement was grouped by expression valence and intensity. We used Growth Curve Analysis to test whether movement patterns were predictable by expression type and participant group. Results show significant interactions between expression type and group, and little effect of emotion valence on ASD expressions. Together, results support perceptions that expressions of individuals with ASD are different from-and more ambiguous than-those of neurotypical individuals'.

Second language processing and revision of garden-path sentences: a visual word study.

We asked whether children's well-known difficulties revising initial sentence processing commitments characterize the immature or the learning parser. Adult L2 speakers of English acted out temporarily ambiguous and unambiguous instructions. While online processing patterns indicate that L2 adults experienced garden-paths and were sensitive to referential information to a similar degree as native adults, their act-out patterns indicate increased difficulties revising initial interpretations, at rates similar to those observed for 5-year-old native children (e.g., Trueswell, Sekerina, Hill & Logrip, 1999). We propose that L2 learners' difficulties with revision stem from increased recruitment of cognitive control networks during processing of a not fully proficient language, resulting in the reduced availability of cognitive control for parsing revisions.

Semantic ambiguity and syntactic bootstrapping: The case of conjoined-subject intransitive sentences.

When learning verb meanings, learners capitalize on universal linguistic correspondences between syntactic and semantic structure. For instance, upon hearing the transitive sentence "the boy is glorping the girl" two-year olds prefer a two-participant event (e.g., a boy making a girl spin) over two simultaneous one-participant events (a boy and a girl separately spinning). However, two- and three-year-olds do not consistently show the opposite preference when hearing conjoined-subject intransitive sentences ("the boy and the girl are glorping"). We hypothesized that such difficulties arise in part from the indeterminacy of the mapping between intransitive syntax and events in the world: a conjoined-subject intransitive sentence can be matched by the one-participant event (if "glorp" means "spin"), both events ("play"), or even the two-participant event ("fight"). A preferential looking study provided evidence for this hypothesis: sentences that plausibly block most non-target interpretations for novel verbs ("the boy and the umbrella are glorping") eliminated the asymmetric difficulty associated with conjoined-subject intransitives. Thus, while conjoined-subject intransitives clearly pose some special challenges for syntax-guided word learning ("syntactic bootstrapping") by novices (Gertner & Fisher, 2012), children's difficulties with this sentence type also reflect expected performance in situations of semantic ambiguity. In discussion, we consider the interacting effects of syntactic- and message-level indeterminacy.

Taking your own path: Individual differences in executive function and language processing skills in child learners.

Children as old as 5 or 6 years display selective difficulties in revising initial interpretive commitments, as indicated by both online and offline measures of sentence comprehension. It is likely, however, that individual children differ in how well they can recover from misinterpretations and in the age at which they become adult-like in these abilities. To better understand the cognitive functions that support sentence processing and revision, the current work investigated how individual differences in children's ability to interpret temporarily ambiguous sentences relate to individual differences in other linguistic and domain-general cognitive abilities. Children were tested over 2 days on a battery of executive function, working memory, and language comprehension tasks. Performance on these tasks was then used to predict online and offline measures of children's ability to revise initial misinterpretations of temporarily ambiguous sentences. We found two measures of children's cognitive flexibility to be related to their ambiguity resolution abilities. These results provide converging evidence for the hypothesis that the ability to revise initial interpretive commitments is supported by domain-general executive function abilities, which are highly variable and not fully developed in children.

Revise and resubmit: how real-time parsing limitations influence grammar acquisition.

We present the results from a three-day artificial language learning study on adults. The study examined whether sentence-parsing limitations, in particular, difficulties revising initial syntactic/semantic commitments during comprehension, shape learners' ability to acquire a language. Findings show that both comprehension and production of morphology pertaining to sentence argument structure are delayed when this morphology consistently appears at the end, rather than at the beginning, of sentences in otherwise identical grammatical systems. This suggests that real-time processing constraints impact acquisition; morphological cues that tend to guide linguistic analyses are easier to learn than cues that revise these analyses. Parallel performance in production and comprehension indicates that parsing constraints affect grammatical acquisition, not just real-time commitments. Properties of the linguistic system (e.g., ordering of cues within a sentence) interact with the properties of the cognitive system (cognitive control and conflict-resolution abilities) and together affect language acquisition.

When two and too don't go together: a selective phonological deficit sparing number words.

We report the case of an Italian speaker (GBC) with classical Wernicke's aphasia syndrome following a vascular lesion in the left posterior middle temporal region. GBC exhibited a selective phonological deficit in spoken language production (repetition and reading) which affected all word classes irrespective of grammatical class, frequency, and length. GBC's production of number words, in contrast, was error free. The specific pattern of phonological errors on non-number words allows us to attribute the locus of impairment at the level of phonological form retrieval of a correctly selected lexical entry. These data support the claim that number words are represented and processed differently from other word categories in language production.