Does endodontics influence radiological detection of external root resorption? an in vitro study.

BACKGROUND: External root resorption (ERR) has a multifactorial etiology and is difficult to diagnose, which means that is continues to be of research interest. This work mainly aims to determine whether external root resorption can be differentially detected in root-filled versus non-endodontically treated teeth using digital periapical radiography (DPR) and cone-beam computed tomography (CBCT). METHODS: The Checklist for Reporting In-vitro Studies (CRIS) guidelines were followed throughout this study. This experiment highlights the preparation and generation of standardized synthetic teeth measured on three-dimensional records converted into Digital Imaging and Communication on Medicine (DICOM) file format. Twelve replicate maxillary incisors were randomized into two groups: (G1) six non-endodontically treated, and (G2) six endodontically treated teeth. In both groups, actual tooth lengths of all specimens were measured and compared with measurements obtained using DPR and CBCT. Simulated ERR lesions [0.12, 0.18, 0.20 mm × 0.5 mm depth in the mesial, distal and palatal apical regions] were created progressively, radiographic images were recorded, and 24 DPRs and 96 CBCTs were obtained in total. Eight blinded, previously calibrated researchers made a total of 1920 measurements (using Horos Software). Data were analyzed using the Shapiro-Wilk, ANOVA, Kruskal-Wallis and Wilcoxon rank post-hoc tests [Bonferroni correction in multiple comparison tests (p < 0.05)]. RESULTS: ICC values for intra- and inter-examiner agreement were appropriate. DPR overestimated ERR detection compared to the actual and CBCT measurements [Mean diff = 0.765 and 0.768, respectively]. CBCT diagnosis of ERR lesions in specimens without root canal treatment was significantly more accurate than DPR diagnoses on both non-endodontically and endodontically-treated specimens [p = 0.044; p = 0.037, respectively]. There was an 18.5% reduction in sensitivity in all DPR diagnoses made on endodontic teeth versus those made on non-endodontically treated teeth. For the smallest ERR lesions, this sensitivity was even more marked, with 27.8 and 25% less sensitivity, respectively. CONCLUSIONS: The results of this study highlight that both CBCT and DPR are good diagnostic methods for ERR. Nevertheless, root canal filling material influences diagnostic capability in ERR. The clinical significance was that the presence of intracanal material reduces the detection and diagnosis of ERR by DPR in teeth with root canal treatment.

FCSlib: an open-source tool for fluorescence fluctuation spectroscopy analysis for mobility, number and molecular brightness in R.

SUMMARY: FCSlib is an open-source R tool for fluorescence fluctuation spectroscopy data analysis. It encompasses techniques such as Fluorescence Correlation Spectroscopy, Number and Brightness, Pair Correlation Function and Pair Correlation of Molecular Brightness. AVAILABILITY AND IMPLEMENTATION: Source code available at https://cran.r-project.org/web/packages/FCSlib/ for Linux, Windows and macOS platforms. Sample data as well as a user's guide are available at https://github.com/FCSlib/FCSlib. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

A genome-wide association study identifies novel gene associations with facial skin wrinkling and mole count in Latin Americans.

BACKGROUND: Genome-wide association studies (GWASs) have identified genes influencing skin ageing and mole count in Europeans, but little is known about the relevance of these (or other genes) in non-Europeans. OBJECTIVES: To conduct a GWAS for facial skin ageing and mole count in adults < 40 years old, of mixed European, Native American and African ancestry, recruited in Latin America. METHODS: Skin ageing and mole count scores were obtained from facial photographs of over 6000 individuals. After quality control checks, three wrinkling traits and mole count were retained for genetic analyses. DNA samples were genotyped with Illumina's HumanOmniExpress chip. Association testing was performed on around 8 703 729 single-nucleotide polymorphisms (SNPs) across the autosomal genome. RESULTS: Genome-wide significant association was observed at four genome regions: two were associated with wrinkling (in 1p13·3 and 21q21·2), one with mole count (in 1q32·3) and one with both wrinkling and mole count (in 5p13·2). Associated SNPs in 5p13·2 and in 1p13·3 are intronic within SLC45A2 and VAV3, respectively, while SNPs in 1q32·3 are near the SLC30A1 gene, and those in 21q21·2 occur in a gene desert. Analyses of SNPs in IRF4 and MC1R are consistent with a role of these genes in skin ageing. CONCLUSIONS: We replicate the association of wrinkling with variants in SLC45A2, IRF4 and MC1R reported in Europeans. We identify VAV3 and SLC30A1 as two novel candidate genes impacting on wrinkling and mole count, respectively. We provide the first evidence that SLC45A2 influences mole count, in addition to variants in this gene affecting melanoma risk in Europeans.

Dielectric spectroscopy of novel bio-based aliphatic-aromatic block copolymers: Poly(butylene terephthalate)-b-poly(lactic acid).

Broadband dielectric spectroscopy has been used to characterize in deep the relaxation behavior of novel bio-based aliphatic-aromatic block copolymers based on poly(butylene terephthalate) (PBT) and poly(lactic acid) (PLA). The results indicate that the copolymerization decreases the ability to crystallize of the resulting block copolymer. The [Formula: see text] relaxation of the block copolymers is consistent with this fact exhibiting initially the characteristics features of an amorphous polymeric material cold crystallizing upon heating. The cold crystallization can be easily visualized by dielectric spectroscopy by a discontinuous and abrupt change of the shape parameters of the [Formula: see text] relaxation. The sub-glass dynamics of the block copolymers is complex and be ascribed to a [Formula: see text] relaxation composed of two local modes, [Formula: see text] and [Formula: see text], which can be assigned to the relaxation in PBT of the bond between the ester oxygen and the aliphatic carbon and to the bond between the aromatic ring carbon to the ester carbon, respectively. With increasing amount of the PLA block the crystallinity decreases as well as the activation energy of the [Formula: see text] mode approaching the expected value for amorphous PBT. On the contrary, the activation energy for the [Formula: see text] exhibits an unexpected increase as the amount of PLA increases. This effect has been explained by considering that at lower temperatures the [Formula: see text] mode of PBT is the more significant while at higher temperatures the [Formula: see text] relaxation of the PLA block becomes the dominant one.

Effect of chemical structure on the subglass relaxation dynamics of biobased polyesters as revealed by dielectric spectroscopy: 2,5-furandicarboxylic acid vs. trans-1,4-cyclohexanedicarboxylic acid.

The chemical structure-dynamics relationship for poly(trimethylene 2,5-furanoate) and poly(trimethylene 1,4-cyclohexanedicarboxylate) was investigated via dielectric spectroscopy and compared with that of poly(trimethylene terephthalate) in order to evaluate the impact on the subglass dynamics of the chemical nature of the ring. Further comparison was accomplished with the neopentyl glycol containing counterparts: poly(neopentyl 2,5-furanoate) and poly(neopentyl 1,4-cyclohexanedicarboxylate). Our study reveals a multimodal nature of the subglass ß process. For the more flexible polymers (containing cyclohexane rings) three modes for the ß process were detected. The faster mode was assigned to the relaxation of the oxygen linked to the aliphatic carbon, the slower one to the link between the aliphatic ring and the ester group, and the third mode to the aliphatic ring. For stiffer polymers (containing aromatic rings), the local modes appear more coupled. This effect is more evident in the polymers with the furan ring where essentially a single ß mode can be resolved.

RNASEH1 gene variants are associated with autoimmune type 1 diabetes in Colombia.

BACKGROUND: In a previous work, we found linkage and association of type 1 diabetes (T1D) to a 12 known gene region at chromosome 2p25 in Colombian families. Here, we present further work on this candidate region. MATERIALS AND METHODS: Seventeen SNPs located on the 12 candidate genes, in 100 familial trios set, were tested by ARMS-tetraprimer-PCR or PCR-RFLP. Five extra SNPs in the vicinity of rs10186193 were typed. A replica phase included 97 novel familial trios, in whom diabetes-related auto-antibodies (AABs) were tested in sera of the patients. In addition to transmission disequilibrium tests, haplotype analyses were carried out using the unphased software. RESULTS: SNP rs10186193 (at RNASEH1 gene) showed association with T1D (P = 0.005). The additional five SNPs revealed that rs7607888 (P = 2.03 × 10-7), rs55981318 (P = 0.018), and rs1136545 (P = 1.93 × 10-9) were also associated with T1D. Haplotype analysis showed association for rs55981318-rs10186193 (P = 0.0005), rs7563960-rs7607888 (P = 0.0007), rs7607888-rs1136545 (P = 9.21 × 10-10), and rs1136545-rs11538545 (P = 6.67 × 10-8). In contrast, the new set of 97 familial trios tested for SNPs rs55981318, rs10186193, and rs7607888 did not support the previous finding; however, by combining the sample (197 trios), evidence of association of T1D with rs55981318 and rs7607888 was conclusive. In addition, a two-loci haplotype analysis of the combined sample showed significant association of RNASEH1 with T1D (P = 3.1 × 10-5). CONCLUSION: In conclusion, our analyses suggest that RNASEH1 gene variants associate with susceptibility/protection to T1D in Colombia.

Long-distance dispersal suppresses introgression of local alleles during range expansions.

During range expansions, even low levels of interbreeding can lead to massive introgression of local alleles into an invader's genome. Nonetheless, this pattern is not always observed in human populations. For instance, European Americans in North America are barely introgressed by Amerindian genes in spite of known contact and admixture. With coalescent spatially explicit simulations, we examined the impact of long-distance dispersal (LDD) events on introgression of local alleles into the invading population using a set of different demographic scenarios applicable to a diverse range of natural populations and species. More specifically, we consider two distinct LDD models: one where LDD events originate in the range core and targets only the expansion front and a second one where LDD events can occur from any area to any other. We find that LDD generally prevents introgression, but that LDD events specifically targeting the expansion front are most efficient in suppressing introgression. This is likely due to the fact that LDD allows for the presence of a larger number of invader alleles at the wave front, where effective population size is thus increased and local introgressed alleles are rapidly outnumbered. We postulate that the documented settlement of pioneers directly on the wave front in North America has contributed to low levels of Amerindian admixture observed in European Americans and that this phenomenon may well explain the lack of introgression after a range expansion in natural populations without the need to evoke other mechanisms such as natural selection.

Are there any differences between first and second primary molar pulpectomy prognoses? A retrospective clinical study.

AIM: To determine if there are any significant differences between the prognoses of pulpectomies done on first and second primary molars of the upper and lower dental arch. MATERIALS AND METHODS: Study Design: The clinical study included 55 children who had undergone 86 pulpectomy treatments, 41 on the first molars and 45 on the second molars. The root canal filling material consisted of a paste based on Walkhoff formula, containing Kri-1, calcium hydroxide and meta-cresol formaldehyde. The same clinician carried out all pulpectomies. RESULTS: After the analysis there were a total of 7 treatment failures (3 in the upper arch and 4 in the lower). Four of the 7 failures were first primary molars and three were second primary molars. STATISTICS: There were no significant differences in the prognoses of the different kinds of primary molars. CONCLUSION: The anatomy of the primary molars changes considerably. Significant differences were not observed in the prognosis of different types of primary molars after pulpectomy.

Effectiveness of Biology-Based Methods for Inhibiting Orthodontic Tooth Movement. A Systematic Review.

INTRODUCTION: Several experimental studies in the literature have tested different biology-based methods for inhibiting or decreasing orthodontic tooth movement (OTM) in humans. This systematic review investigated the effects of these interventions on the rate of tooth movement. STUDY DESIGN: Electronic [MedLine; SCOPUS; Cochrane Library; OpenGrey;Web of Science] and manual searches were conducted up to January 26th, 2016 in order to identify publications of clinical trials that compared the decreasing or inhibiting effects of different biology-based methods over OTM in humans. A primary outcome (rate of OTM deceleration/inhibition) and a number of secondary outcomes were examined (clinical applicability, orthodontic force used, possible side effects). Two reviewers selected the studies complying with the eligibility criteria (PICO format) and assessed risk of bias [Cochrane Collaboration's tool]. Data collection and analysis were performed following the Cochrane recommendations. RESULTS: From the initial electronic search, 3726 articles were retrieved and 5 studies were finally included. Two types of biology-based techniques used to reduce the rate of OTM in humans were described: pharmacological and low-level laser therapy. In the first group, human Relaxin was compared to a placebo and administered orally. It was described as having no effect on the inhibition of OTM in humans after 32 days, while the drug tenoxicam, injected locally, inhibited the rate of OTM by up to 10% in humans after 42 days. In the second group, no statistically significant differences were reported, compared to placebo, for the rate of inhibition of OTM in humans after 90 days of observation when a 860 nm continuous wave GaAlA slow-level laser was used. CONCLUSIONS: The currently available data do not allow us to draw definitive conclusions about the use of various pharmacological substances and biology-based therapies in humans able to inhibit or decrease the OTM rate. There is an urgent need for more sound well-designed randomized clinical trials in the field.

Radiotherapy Learning in Medical Undergraduate Courses.

Approximately 60 % of all cancer patients receive radiotherapy as a component of their treatment. Radiation Oncology concepts, specifically, are not formally introduced to students in most traditional school curricula until their clinical rotations or may only be included as an optional elective during the core clinical clerkships. The aim of this study is to determine whether the teaching of Radiation Oncology by radiation oncologists, in the third year, in block diagnostic and therapeutic procedures, is helpful for student training and changes their attitude towards the specialty. We administered a pre-test and post-test examination of the concepts in general radiation oncology, radiation physics, radiobiology, breast cancer and their opinion to the third year medical students. The 10-question, multiple choice tests were administered before starting the lessons and when they finished the course. Of the 130 third year students, 95 (73.07 %) participated in the pre-test and post-test analysis. For the entire cohort, improvement was seen in all questions except one regarding physics. A statistically significant improvement (p < 0.005) was seen in the question regarding the aspects of general radiotherapy, radiobiology, acute and after-effects of radiation and the management of early-stage breast cancer. With an adequate methodology, third year students can learn aspects of Radiation Oncology.

Ocular and craniofacial phenotypes in a large Brazilian family with congenital aniridia.

Congenital aniridia is a rare genetic disorder characterized by varying degrees of iris hypoplasia that are associated with additional ocular abnormalities. More than 90% of the causal mutations identified are found in the PAX6 gene, a transcription factor of critical importance in the process of neurogenesis and ocular development. Here, we investigate clinical, molecular, and craniofacial features of a large Brazilian family with congenital aniridia. Among the 56 eyes evaluated, phenotype variation encompassed bilateral total aniridia to mild iris defects with extensive variation between eyes of the same individual. PAX6 molecular screening indicated a heterozygous splice mutation (c.141 + 1G>A). Thus, we hypothesize that this splicing event may cause variation in the expression of the wild-type transcript, which may lead to the observed variation in phenotype. Affected individuals were more brachycephalic, even though their face height and cephalic circumference were not significantly different when compared to those of non-affected relatives. From this, we infer that the head shape of affected subjects may also be a result of the PAX6 splice-site mutation. Our data summarize the clinical variability associated with the ocular phenotype in a large family with aniridia, and help shed light on the role of PAX6 in neurocranial development.

[Online platforms for neuropsychological rehabilitation: current status and lines of work]. / Plataformas de rehabilitación neuropsicológica: estado actual y líneas de trabajo.

INTRODUCTION: The incidence of neurological and psychiatric diseases and disorders has increased in recent years, and similarly, the number of technological tools facilitating neuropsychological rehabilitation for family members and therapists has also grown. The purpose of this article is to describe some of these tools and indicate the needs they cover. DEVELOPMENT: This article reviews some currently well-known neuropsychological rehabilitation platforms, compares them, and proposes future lines of work to be considered when developing tools that meet real needs. In this review, we list the main advantages and shortcomings of each of the tools and establish benchmarks for evaluating them. In comparing these platforms, we may observe their advantages on the one hand, and areas needing improvement on the other. CONCLUSIONS: This review demonstrates that more of these tools are entering the market, but many aspects of neurorehabilitation remain uncovered. Additional studies evaluating these tools' effectiveness are also needed.

Intrusive Luxation in Primary Teeth: A Case Report.

BACKGROUND: Intrusive luxation, also called central dislocation, is often the result of an axial impact in the apical direction, moving the tooth within the alveolar bone. This is possibly one of the most traumatic injuries, since the displacement of a tooth within its socket implies extensive and acute involvement of the periodontal ligament, bone damage and rupture of the neurovascular bundle. The close relationship between the apexes of the primary teeth and the developing permanent successor in turn can lead to multiple complications, which are greater when the permanent tooth is affected in the early stages of development. METHODS: The present paper describes a case of intrusion in primary teeth and its evolution following initial diagnosis as avulsion at the time of trauma. RESULTS: The upper right central incisor, initially diagnosed as avulsed, was lodged in the floor of the right nostril, and was surgically extracted through the nose. CONCLUSIONS: In cases of intrusion of primary teeth, it is essential to diagnose the direction of the displaced tooth to rule out injury to the successor and thus prevent the occurrence of sequelae in the permanent dentition.

Impact of immediate loading on early soft tissue healing at two-piece implants placed in fresh extraction sockets: an experimental study in the beagle dog.

OBJECTIVES: To study early soft tissue healing of immediately placed implants with or without immediate loading in the dog. MATERIAL AND METHODS: Forty-eight implants were placed in the distal sockets of Pm3 and Pm4 in the lower jaw of 12 beagle dogs immediately after tooth extraction. In the control group, no loading was applied. In the test group, an immediate loading restoration with occlusal contacts was performed. Dogs were sacrificed at 2, 4, and 8 weeks for histological analysis. RESULTS: At the end of the study, there was a 100% implant and prosthesis survival. The biological width dimension was similar in both groups at all the studied healing periods. This dimension tended to decrease from week 2 to 8 in both groups, on both the buccal and lingual side. The barrier epithelium tended to stop at the implant-abutment interface in both groups and also decreased in length from week 2 to 8, on the buccal and the lingual side. Soft tissue recession remained low and occurred mainly in the test group. CONCLUSIONS: The characteristics, dimension, and healing pattern of the peri-implant soft tissues were similar around immediate implants with or without immediate loading.

Osteopontin gene SNPs (rs9138, rs11730582) mediate susceptibility to external root resorption in orthodontic patients.

OBJECTIVE: External apical root resorption (EARR) is a frequent iatrogenic effect of orthodontic treatment. Substantial variability in responses to postorthodontic EARR has been observed among patients even when similar treatment protocols were used. This observation suggests that environmental and/or genetic variations between individuals may confer susceptibility or resistance to developing EARR. The objective of this study is to determine whether variants in the osteopontin gene, an essential mediator in the odontoclast fusion and attachment process, are positively/negatively associated with postorthodontic EARR. MATERIALS AND METHODS: Genetic screening of eighty-seven orthodontic patients was performed for two polymorphisms in the osteopontin gene cluster (rs9138 and rs11730582). Subjects were divided into groups, according to the presence or absence of EARR (>2 mm). Genotype distributions and allelic frequencies were calculated using the chi-square test. Logistic regression analysis was used to assess the extent to which clinical-related parameters interfered with the EARR. Odds ratios (OR) and 95% confidence intervals were also calculated. RESULTS: Data from this study show that subjects heterozygous and homozygous for the most frequent allele of the osteopontin gene at position 89261521 [OR: 0.035 (P = 0.035*) (allele A)] and 89253600 [OR: 0.20 (P = 0.025*) (allele T)], respectively, are protected against postorthodontic EARR. Nevertheless, a highly significant association was found in the comparative analysis of homozygous subjects [2/2 (CC)] for the osteopontin gene (rs9138), resulting in an increased risk of suffering postorthodontic EARR[OR: 4.10; P = 0.045*; CI: 95%]. Subjects who were homozygous [2/2 (CC)] for the osteopontin gene (rs11730582) were more likely, and to a greater extent, to be affected with EARR [OR: 11.68; P < 0.039*; CI: 95%] compared with other genotypes. CONCLUSION: Variations in the osteopontin gene (rs9138 and rs11730582) are determinants of a genetic predisposition to suffer EARR secondary to orthodontic treatment.

Revascularization of immature permanent teeth with apical periodontitis.

The aim of this minireview was to identify and review the scientific evidence regarding regenerative endodontic protocols claiming to revascularize permanent immature teeth with apical periodontitis. The literature was identified using the PubMed/MEDLINE, Scopus, Scirus, EMBASE and Cochrane databases up to February 2013. Studies were selected independently by two different researchers (kappa index: 0.88), based on established inclusion/exclusion criteria. The methodological quality of the reviewed papers was classified as high, medium or low (HQ, MQ, LQ). The search strategy identified 285 titles. Nine studies, both human and animal based, were selected after application of the criteria (LQ:5; MQ:4). In most of these studies (seven of nine), the revascularization protocol included a triple antibiotic combination as canal disinfectant for a period of 1-4 weeks after blood clot formation (LQ:5; MQ:4), although there is no clear consensus about the treatment protocol. Two studies reported tooth discoloration after the revascularization process (LQ:2), and only three (LQ:1; MQ:2) reported a success rate of 54.9% in dogs and 73.6% and 80% in humans, respectively. Revascularization of immature permanent teeth with apical periodontitis is possible and preferable to apexification. Nevertheless, there is a widespread lack of randomized clinical trials and blinded measures. In addition, the small sample sizes that are common in these studies as well as the generally low quality of the analysed publications require the results to be viewed with caution. There is a high risk of bias, with a low quality of available information, for developing clinical guidelines for regenerative endodontic protocols; rigorous randomized clinical trials are therefore needed.

A new indicator of the oral hygiene habits of disabled persons: relevance of the carer's personal appearance and interest in oral health.

OBJECTIVE: To investigate whether there is a relationship between the oral hygiene habits of individuals with severe disability the carer's personal appearance and interest in oral health. PATIENTS AND METHODS: The study group was formed of 60 disabled persons and their respective carers who came for the first time to consultation in the Special-Needs Dentistry Unit of the University of Santiago de Compostela, Spain. All the carers answered a standardised questionnaire of 28 questions divided into four sections: disabled individual's demographic data, disabled individual's general medical details, social aspects of the carer (personal appearance of the carer and interest in oral health), and disabled individual's oral hygiene habits. The personal appearance of the carers and their interest in the disabled individual's oral health were evaluated using independent scales designed specifically for the study, with five binary items in each scale. RESULTS: The carer's personal appearance and interest in the disabled individual's oral health showed a statistically significant relationship with the individual's oral hygiene habits, particularly with respect to the frequency and duration of toothbrushing, need for physical restraint during toothbrushing, use of a manual toothbrush and use of toothpaste. CONCLUSIONS: The carer's personal appearance and interest in the disabled individual's oral health are good indicators of the oral hygiene habits of an individual with severe disability. Consideration should be given to the inclusion of these aspects as a complementary element of the dental record.

Association between craniofacial asymmetry and unilateral temporomandibular joint sounds in adult patients using 3D-computed tomography.

OBJECTIVES: The purpose of this study was to investigate the possible relationship between unilateral temporomandibular joint (TMJ) sounds and craniofacial asymmetry, using 3D-computed tomography (CT) measurements. SUBJECTS AND METHODS: Forty-one reconstructed 3D-CT models of adult subjects were measured to analyze craniofacial asymmetry. Subjects were divided into two groups depending on the presence (n = 20) or absence (n = 21) of unilateral joint sounds, and the results compared using the Mann-Whitney U-test. To investigate the association between these parameters, the Pearson correlation coefficient was calculated. RESULTS: Asymmetries in the maxillary and mandibular structures were statistically significant (P < 0.05) for subjects with unilateral TMJ sounds and for controls, except in the case of maxillary rotation and mandibular ramus height (P > 0.05). The highest deviations found were frontal and lateral ramal inclination, goniac angle and canting of occlusal plane. CONCLUSIONS: Adult patients with unilateral joint sounds may have skeletal jaw asymmetry and a canted occlusal plane.

A new three-dimensional analysis of asymmetry for patients with craniofacial syndromes.

OBJECIVES: The use of three-dimensional computed tomography (3D-CT) analyses represents a substantial improvement in planning treatment. The aim of this study is to introduce a new three-dimensional (3D) analysis of clinical value for evaluating asymmetry in cases of craniofacial syndrome. SUBJECTS AND METHODS: Virtual 3D models were reconstructed from CT images of 62 normal subjects (35 males and 27 females), more than 18 years old. Measurements of asymmetrical skeletal and dentoalveolar relationships were evaluated and standardized data obtained. The feasibility of the new 3D craniofacial analysis was then evaluated on one patient with severe maxillomandibular asymmetry in the form of hemifacial microsomia. RESULTS: Standardized 3D data from the analysis were obtained and classified into 6 maxillary measurements, eight mandibular measurements and seven dentoalveolar process measurements. No significant differences were found between males and females (U-Mann-Whitney test, P > 0.05). Useful data of clinical value was provided for planning orthodontic and surgical treatment of asymmetries, as well as a diagnostic chart. CONCLUSION: This method is useful for the clinical evaluation of asymmetry in craniofacial syndromes. The use of 3D analysis facilitates surgical and orthodontic treatment planning.

Do the smiles of the world's most influential individuals have common parameters?

The aim of this study was to determine - on the basis of the most recent yearly listings - whether there were any common measurable variables associated with the smiles of the world's most influential people. A total of 168 subjects were selected from the lists of Time magazine's 100 most influential people during the period 2006-2010. Smiling frontal view photographs were obtained. Thirty-six variables for each subject were traced and measured using photogrammetric analysis to obtain qualitative and quantitative proportions and measurements. Differences with respect to gender, occupation and year of listing were tested to 95% significance, using the Student's t-test and the Kruskal-Wallis test. The chi-squared test was used for qualitative variables. Irrespective of gender or occupation, the similar quantifiable characteristics of the smiles of the most influential subjects were the following: vertical upper lip proportion, smile width, incisor exposure, buccal corridor ratio, smile symmetry index and intra-dental proportions (P > 0·05). Other qualitative standards were as follows: smile symmetry, the buccal corridors and smile arc, direction of occlusal cant and the degree of deviation between maxillary and facial midlines. Differences were found for gingival display and smile height parameters (P = 0·001). The smiles of the world's most influential people revealed common standards, regardless of occupation or gender, which may play a decisive role in the expressions of influential faces.