Orthodontic problems among string and wind instrument players.

BACKGROUND: Specific occlusion problems are caused by playing with wind and string musical instruments for a long time. The aim of the work was to establish the orthodontic problems among piano, string and wind instrument players. METHODS: The sample of the research included 167 students of musical education institutions in Lithuania. Participants were divided into three groups: 52 string (violin and viola) students, 46 wind students and 69 piano students as a control group. They were investigated clinically according to the ICON index. The facial profile was estimated and a questionnaire was given. RESULTS: More than half of the participants had a convex facial profile, 37.7% - straight and only 4.2% - concave. In total 35.3% of participants and even 61.5% of string students had a crossbite. 1/3-2/3 overlap of the incisors was more frequent in wind instrument players group than in other groups. The average of all participants' ICON index reached 28.79±15.01 scores: higher values were estimated for violinists and males. Students with crossbite played more hours than without crossbite. A cusp-to-cusp molar relationship (4034.7 hours) was observed in players who played more hours. CONCLUSIONS: Playing the violin might predispose crossbite and playing wind instruments - deep bite.

Heritability of mandibular asymmetries in sagittal direction: A cephalometric study.

AIM OF THE WORK: If we figure out mandible asymmetry etiology, we can inspire further scientific research, create more effective treatment schemas and recommend means of prophylaxis that could stop mandible asymmetry development. The aim of this work was to analyze monozygotic and dizygotic twins' mandibular asymmetry in sagittal direction using cephalometric data and to analyze its dependence of genetic and environmental factors. MATERIAL AND METHODS: Study sample consisted of 80 dizygotic (DZ) and 80 monozygotic (MZ) twins of same sex. 3 cephalometric measurements were made to determine mandible asymmetry in sagittal direction. Indexes of mandibular asymmetry (IMA1, IMA2) were calculated. Data analysis was done using Microsoft Excel (2013). Genetic and environmental factors influencing mandible asymmetry was determined. RESULTS: Mandibular dental asymmetry was bigger in monozygotic twins' group but the results were not statistically significant. Mandibular skeletal asymmetry was significantly bigger in dizygotic twins' group: IMA1(DZ)=3.05±1.94, IMA1(MZ)=1.92±1.05, p=0.005. IMA2(DZ)=3.12±2.04, IMA2(MZ)=1.88±1.04, p=0.004. Distance between distal borders of the ramus is mostly determined by genetic factors. CONCLUSIONS: 1. Mandibular skeletal asymmetry was significantly bigger in dizygotic twins' group. Mandibular dental asymmetry and symmetry did not differ in groups significantly. 2. Skeletal mandible's asymmetry is more determined by genetics than environmental factors, but lower molars' sagittal position is determined more by environment.

Orthodontic treatment complexity, outcome and need among school age patients of Lithuanian university of health sciences clinic of orthodontics.

AIM OF THE WORK: It has not been any well-documented study describing the prevalence of orthodontic anomalies between school-age children seeking orthodontic treatment at LUHS (Lithuanian university of health sciences) clinic of Orthodontics. Our aim was to assess the prevalence of orthodontic problems and to determine orthodontic treatment need, complexity and outcome for school-age patients who were treated at LUHS clinic of Orthodontics. MATERIAL AND METHODS: Our study sample consists of 336 scholars 6-19 years old who were treated at LUHS clinic of orthodontics from 2013 to 2018. ICON index is used to determine the complexity, outcome and need of orthodontic treatment. Statistical analysis is performed using the statistical software package IBM SPSS Statistics 24.0. Quantitative variable distribution is assessed visually and by using the Shapiro-Wilk test. RESULTS: The estimated need for orthodontic treatment is 56.3 percent among patients. The need of treatment for 6-10 year old group is significantly higher than for 11-14 and 15-19 groups (69.0, 52.3 and 51.2 percent). In the group of 11-14 year olds the need of treatment between boys and girls differs significantly (63.1 percent in boy group, 43.8 percent in girl group). Moreover in the 11-14 year old group, the complexity of treatment "easy" is more frequent than in the 6-10 group. CONCLUSIONS: The need of orthodontic treatment is 56.3 percent among subjects treated in LUHS clinic of orthodontics from 2013 to 2018. In all age groups the complexity of treatment is mostly "easy" or "mild".

Smile aesthetics as perceived by dental students: a cross-sectional study.

BACKGROUND: An aesthetic smile has a number of components, and people generally equate a good dental appearance with success in many areas of life. The features that determine smile aesthetics could provide significant insights into post-treatment satisfaction and may predict a patient's objectives when undergoing treatment. The purpose of this study was to evaluate how smile characteristics are perceived by dental students. METHODS: The study was performed in 431 local and international dental students at the Lithuanian University of Health Sciences. The study data were collected using a three-part questionnaire. The first part of the questionnaire included sociodemographic items, i.e., student gender, age, nationality, and years of study; the second consisted of questions about facial aesthetic features; and the third elicited responses to photographs of 17 different smiles retrieved from the Lithuanian University of Health Sciences Clinic of Orthodontics database. The smile aesthetics were evaluated according to their dentolabial, dentogingival, dental, and dental arch characteristics using a 5-point numeric rating scale (1, best; 5, worst). The data were analysed using the Pearson's chi-square and Mann-Whitney U tests. RESULTS: The study included 336 local and 95 international dental students (132 men [30.6%], 299 women [69.4%]). Significantly more women than men focused on a person's teeth when communicating (41.5% vs.32.6%, p < 0.005). Women were more critical than men when evaluating gingival smile, the 'golden proportion', occlusal cant, and dental crowding. The most unfavourable smile characteristics were identified in the dental analysis category, with hypodontia ranked as the worst smile feature (mean numeric rating scale score 4.71). CONCLUSION: Among dental students, the most distracting characteristics of a smile when determining its attractiveness were hypodontia, gingival smile, a reversed curvature of the occlusal plane, and dental crowding.

Impact of genetics on third molar agenesis.

The purpose of this investigation was to determine the impact of heritability on third molar agenesis in twins. The study sample consisted of 284 same sex twins (172 monozygotic and 112 dizygotic), whose mean ages were 19.7 ± 4.3 and 18.9 ± 4.8 years, respectively. The monozygotic group consisted of 36.3% males and 63.7% females, while the dizygotic group consisted of 50.1% males and 49.9% females. The zygosity of the twins was established using 15 specific DNA markers. The prevalence of third molar agenesis in monozygotic twins was 19.6%, which was higher than in the dizygotic twins group (15.50%) (p = 0.004). In both groups, third molar agenesis was more frequent in the maxilla than in the mandible (p = 0.000). Agenesis of the maxillary third molars was mostly affected by additive genetic factors (62-63%), with the common environment and the specific environment accounting for up to 25% and 13%, respectively. In contrast, agenesis of the lower third molars was associated with a higher additive genetic determination (81-83%), with the specific environment accounting for 17% to 19%. The study's conclusion is that the formation of the third molars follicle is strongly controlled by additive genetic factors.

The magnification in the lower third and second molar region in the digital panoramic radiographs.

BACKGROUND: The aim of this study was to determine the accuracy of linear measurements of the lower third and second molar crowns in the digital panoramic radiographs and to compare them with plaster models as the calibration standard. MATERIALS AND METHODS: The digital panoramic radiographs and plaster models of the orthodontic patients were used in the study. Standardized metal calibration gauges (MCGs) were bonded to the buccal surface of the lower molars bilaterally. Measurements in the panoramic radiographs were done using Dolphin Imaging 11.8 Premium program. RESULTS: Forty-one panoramic radiographs and diagnostic plaster models of the orthodontic patients (mean age 18.45 ± 2.35) were analyzed. Eighty-two lower third molars, 82 second molars, and 82 first molars were evaluated. The magnification coefficients (MCC) calculated according to the plaster models ranged from 1.07 to 1.08. The magnification coefficients calculated according to the bonded MCG were about 1.04. The differences between the teeth groups and right-left sides were not statistically significant (P > 0.05). Spearman correlation showed a positive medium correlation between the magnification using the calibration with plaster models and metal gauges (P < 0.05). CONCLUSIONS: The magnification in the lower first, second, and third molars regions showed almost the same values. The calculation of magnification coefficient using bonded metal calipers was more accurate than calculation according to the plaster models, but the differences were not statistically significant. The use of the plaster models for calibration of the magnification coefficient in the good-positioned lower molars' region might be used as an alternative to the bonded MCGs.

The effect of the teeth bleaching with 35% hydrogen peroxide on the tensile bond strength of metal brackets.

The objective of this study was to determine the effects of teeth bleaching on the tensile bond strength of metal brackets bonded with light-curing adhesive system to the human enamel. 40 recently extracted human permanent molars were used for the study. The mesial buccal surface of each tooth was used as a control group and the distal buccal surface was used as an experimental group. Control group surfaces were not submitted to bleaching, while experimental group surfaces were bleached with in-office bleaching material containing 35% hydrogen peroxide. 30 days after the bleaching, identical premolar metal brackets were bonded to each surface using light-curing adhesive. Both groups were submitted to a tension test, using a universal machine. The tensile bond strength of brackets bonded to the bleached enamel was 15% lower than that of brackets bonded to the unbleached enamel. After debonding, more adhesive was left on the bracket base in experimental group than in the control group. The conclusion of this study was that bleaching with an in-office bleaching material containing 35% hydrogen peroxide reduced the tensile bond strength of orthodontic bracket adhesive to the enamel surface.

Relationship between malocclusion, soft tissue profile, and pharyngeal airways: A cephalometric study.

BACKGROUND AND OBJECTIVE: The recent years have been marked by a search for new interrelations between the respiratory function and the risk of the development of malocclusions, and algorithms of early diagnostics and treatment have been developed. The aim of the study was to evaluate the relationships between hard and soft tissues and upper airway morphology in patients with normal sagittal occlusion and Angle Class II malocclusion according to gender. MATERIALS AND METHODS: After the evaluation of clinical and radiological data, 114 pre-orthodontic patients with normal or increased ANB angle, were randomly selected for the study. The cephalometric analysis was done by using the Dolphin Imaging 11.8 computer software. RESULTS: Comparison of the cephalometric values of soft tissue and airway measurements performed statistically significant negative correlation between the width of the upper pharynx and the ANB angle was found: the ANB angle was decreasing with an increasing width of the upper pharynx. The airways showed a statistically significant negative correlation between the width of the lower pharynx and the distance from the upper and the lower lips to the E line. Logistic regression analysis was performed to evaluate significant factors that could predict airway constriction. The upper pharynx was influenced by the following risk factors: a decrease in the SNB angle, an increase in the nose tip angle, and younger age; while the lower pharynx was influenced by an increase in the distance between the upper lip and the E line and by an increase in the upper lip thickness. CONCLUSIONS: During critical period of growth and development of the maxillofacial system, the patients with oral functional disturbances should be monitored and treated by a multidisciplinary team consisting of a dentist, an orthodontist, a pediatrician, an ENT specialist, and an allergologist. Cephalometric analysis applied in our study showed that Angle Class II patients with significantly decreased facial convexity angle, increased nasomental, upper lip-chin, and lower lip-chin angles, and upper and lower lips located more proximally to the E line more frequently had constricted airways.

Heritability estimates of dental arch parameters in Lithuanian twins.

BACKGROUND: The genetic influence on dental arch morphology may be country-specific, thus it is reasonable to check the estimates of genetics across different populations. The purpose of this study was to evaluate the heredity of dental arch morphology in the sample of Lithuanian twins with accurate zygosity determination. MATERIAL AND METHODS: The study sample consisted of digital dental models of 40 monozygotic (MZ) and 32 dizygotic (DZ) twin pairs. The estimates of heritability (h(2)) for dental arch breadth and length were calculated. RESULTS: All dental arch breadths and lengths were statistically significantly larger in men than in women. Arch length differences between genders were less expressed than largest breadth differences. In the upper jaw the largest genetic effect was found on the arch breadth between lateral incisors. The heritability of dental arch length demonstrated similar differences between upper and lower jaw with mandible dental arch length being more genetically determined. CONCLUSIONS: The largest genetic impact was found on the upper dental arch breadth between lateral incisors. Similar, but lower heritability is inherent for canines and first premolars of the upper jaw and first premolars of the lower jaw. It also can be noted, that arch breadths between posterior teeth show lower heritability estimates than between anterior teeth on both jaws. The dental arch in the upper jaw has more expressed genetic component than in the lower jaw.

Assessment of skeletal and dental pattern of Class II division 1 malocclusion with relevance to clinical practice.

Class II division 1 malocclusion represents the most common skeletal discrepancy which orthodontists see in daily practice. The understanding of the morphology is a key element in planning dentofacial orthopedic treatment for this type of malocclusion. The purpose of the present study was to examine prepubertal children with Class II division 1 malocclusion and to evaluate maxillary and mandibular skeletal positions in comparison with normal growth standards by means of cephalometric measurements used by clinical practitioners. For the study casts and cephalograms of 86 consecutive patients with Class II division 1 malocclusion were used. The Class II division 1 malocclusion demonstrates broad variation in its skeletal and dental morphology. The retrognathic mandible (60%), maxillary prognathism (55.8%) and reduce vertical skeletal jaw relationship is the most common characteristic of Class II division 1 malocclusion. The optimal correction of the anteroposterior and vertical dental and skeletal discrepancies could be designed on the base of individual diagnosis for every Class II division 1 patient.

Mandibular pubertal growth spurt prediction. Part one: Method based on the hand-wrist radiographs.

Many orthodontic treatment modalities will yield a better result in less time if properly correlated with the unique facial growth patterns of the patients. The pubertal growth spurt depends on gender and varies in relationship to the chronologic age. General skeletal maturity usually is used as an indicator to predict timing of mandibular growth velocity peak. Hand-wrist radiographic evaluation is one of the diagnostic tools currently available to determine whether the pubertal growth has started, is occurring or has finished. The overview of topic related literature and skeletal maturity assessment (SMA) system developed by L. Fishman are presented. The SMA system is based on eleven discrete adolescence skeletal maturational indicators of hand-wrist bones, covering the entire period of adolescent development. Maturational stage and level demonstrated close correlation with maxillary and mandibular growth velocity, amount of incremental growth and timing. Clinical indications for the use of hand-wrist radiographs to assess skeletal maturity are provided.