Trueness and precision of complete arch dentate digital models produced by intraoral and desktop scanners: An ex-vivo study.

OBJECTIVES: The study aimed to compare the trueness and precision of five intraoral scanners (Emerald S, iTero Element 5D, Medit i700, Primescan, and Trios 4) and two indirect digitization techniques for both teeth and soft tissues on fresh mandibular and maxillary cadaver jaws. METHODS: The maxilla and mandible of a fully dentate cadaver were scanned by the ATOS industrial scanner to create a master model. Then, the specimens were scanned eight times by each intraoral scanner (IOS). In addition, 8 polyvinylsiloxane (PVS) impressions were made and digitized with a Medit T710 desktop scanner. Stone models were then poured and again scanned with the desktop scanner. All IOS, PVS, and stone models were compared to the master model to calculate the mean absolute surface deviation for mandibular teeth, maxillary teeth, and palate. RESULTS: For mandibular teeth, the PVS trueness was only significantly better than the Medit i700 (p < 0.001) and Primescan (p < 0.05). In maxillary teeth, the PVS trueness was significantly better than all IOSs (p < 0.05-0.001); the stone trueness was significantly better than Emerald S (p < 0.01), Medit i700 (p < 0.001) and Primescan (p < 0.01). In the palate, PVS and stone trueness were significantly lower than the iTero Element 5D (p < 0.01) and Trios 4 (p < p < 0.01). Stone trueness was significantly lower than the Medit i700 (p < 0.05). The precision in the palate was significantly lower for PVS and stone than for Emerald S (p < 0.01, p < 0.05), iTero Element 5D (p < 0.01, p < 0.01), Primescan (p < 0.001, p < 0.001), and Trios 4 (p < 0.001, p < 0.01). Significant differences in trueness between the IOSs were observed only in the mandibular teeth. The Medit i700 performed worse than Emerald S (p < 0.01) and iTero Element 5D (p < 0.01). For mandibular teeth, the Medit i700 was significantly more precise than Primescan (p < 0.01) and the Emerald S (p < 0.05). The Trios 4 was significantly less precise than Emerald S (p < 0.05). The precision of Medit i700 was significantly worse than iTero Element 5D (p < 0.01) for maxillary teeth, as well as the Primescan (p < 0.01) and Trios 4 (p < 0.05) for the palate. CONCLUSIONS: In general, indirectly digitized models from PVS impressions had higher trueness than IOS for maxillary teeth; precision between the two methods was similar. IOS was more accurate for palatal tissues. The differences in trueness and precision for mandibular teeth between the various techniques were negligible. CLINICAL SIGNIFICANCE: All investigated IOSs and indirect digitization could be used for complete arch scanning in mandibular and maxillary dentate arches. However, direct optical digitization is preferable for the palate due to the low accuracy of physical impression techniques for soft tissues.

Dental arch form and interdental widths evaluation in adult Caucasian patients with obstructive sleep apnea syndrome.

OBJECTIVE: To evaluate the hypothesis that dental arch form and inter-canine, inter-premolar, and inter-molar widths differ between OSAS patients and non-snoring, non-apneic controls. METHODS: Dental digital models from 64 OSAS patients and 64 control subjects were used to obtain dental arch forms and to compare them between the two groups. Arch forms were extracted from the lower arch models using a professional graphics program and an orthodontic digital template. Through an orthodontic software, inter-molar, inter-premolar, and inter-canine widths were measured for both upper and lower arches. RESULTS: The dental arch forms distribution differed between OSAS patients and controls. OSAS patients had reduced inter-canine, inter-premolar, and inter-molar widths for both arches compared to controls. DISCUSSION: These results suggest that OSAS patients have narrower and more tapered arches than controls. Dental arch morphology and interdental widths differ between OSAS and control groups, supporting the hypothesis that they are an etiological factor.

Dental arch characteristics among South Indian twins - A morphometric study

Genetic and environmental factors are essential in occlusal variations and malocclusion and have been of considerable interest to orthodontists. Studies on twin pairs are one of the most effective methods for investigating genetically determined occlusal variables. Many studies have focused on distances between first molars or between canines but malocclusions can also occur in other regions of the dental arch. Aim: To evaluate the characteristics of the dental arch between pairs of Monozygotic (MZ) and Dizygotic (DZ) twins from Southern India. Methods: A random sample of 51 twin pairs (12­18years old) participated in this study. The zygosity of twin pairs was recorded by facial appearance. The occlusion of the first permanent molars was recorded according to Angle's classification. Study models were prepared to assess dental arch characteristics (i.e., arch form, arch perimeter, arch length; intercanine, intermolar width, and teeth size discrepancy). The obtained data was statistically analyzed using SPSS software 19.0. The student's t-test (two-tailed, independent) and Chi-square test was used to determine the significance of studied parameters. Results: Angle's Class I molar relation was more commonly observed followed by the Class II molar relationship among twins. The measured dental arch dimensions did not show a statistically significant difference among twin pairs. The ovoid arch form was commonly observed among Monozygotic and Dizygotic Twins. There was a similarity among MZ and DZ twins in the anterior and overall Bolton's ratio. Conclusion: There were similar occurrences of measured parameters among twins, which showed genetic predominance in the expression of measured dental arch traits

The Relation among Teeth and Maxillary Dental Arch Dimensions with Anterior Teeth Angulation and Inclination.

OBJECTIVES: This study aimed at finding out whether anterior teeth angulation and inclination have a relationship with the maxillary teeth and dental arch dimensions. METHODS: Fifty study models with normal occlusion were selected from the archive of the Department of Orthodontics at Baghdad Dental Faculty. Maxillary dental arch width and length at different points were determined in addition to measuring anterior teeth angulation, inclination, crown thickness, overjet, overbite, and Bolton's ratios. The unpaired t-test and Pearson's correlation coefficient test were used for data analysis. RESULTS: No statistical gender differences were reported in all measurements except the dental arch widths and length where males had significantly higher mean values. Only the maxillary incisor's inclination showed a direct weak significant correlation with the total arch length. CONCLUSIONS: The inclination of upper incisors had a minimal effect on increasing dental arch length.

Sex estimation from maxillary arch measurements in Egyptian populations: cross-sectional study / Estimación sexual a partir de mediciones del arco maxilar en poblaciones egipcias: estudio transversal

SUMMARY: Sex estimation is an essential step in personal identification and a cornerstone for developing biological profile from skeletal remains. The present study aimed to evaluate the role of maxillary arch widths and lengths as unique parameters in the estimation of sex in Egyptian populations. Maxillary arch measurements were collected from 1410 subjects where palatal impressions were obtained from each participant. Fourteen maxillary inter-teeth widths and lengths that excluded teeth dimensions were included The current study revealed that among the studied population, Egyptian men showed significant differences (p34.57 mm, it could predict the sex with sensitivity of 69.8 %, specificity of 58.8 % and p<0.05. The first molar could be considered as one of the most valid and reliable teeth in estimating sex in Egyptian populations. These measurements may be used as a reference in different populations in cases of mass disaster or relevant events.

RESUMEN: La estimación del sexo es un aspecto esencial en la identificación personal para desarrollar el perfil biológico a partir de restos óseos. El presente estudio tuvo como objetivo evaluar el papel del ancho y longitud del arco maxilar como parámetros únicos en la estimación del sexo en poblaciones egipcias. Se obtuvieron medidas del arco maxilar de 1410 sujetos, además de las impresiones palatinas de cada participante. El estudio actual reveló que entre la población estudiada, los hombres egipcios mostraron diferencias significativas (p 34,57 mm, podría predecir el sexo con sensibilidad de 69,8 %, especificidad de 58,8 % y p <0,05. El primer molar podría considerarse como uno de los dientes más confiables para estimar el sexo en las poblaciones egipcias. Estas mediciones se pueden utilizar como referencia en diferentes poblaciones en casos de desastres masivos o eventos relevantes.

Prevalence of Tympanostomy Tube Placement in Relation to Cleft Width and Type.

OBJECTIVES/HYPOTHESIS: The prevalence of tympanostomy tube surgery (TTS) in patients with a cleft deformity was investigated, in relation to cleft width and cleft type. STUDY DESIGN: Retrospective review of medical health records. METHODS: Retrospective review of medical health records. Seventy-eight patients with non-syndromic cleft deformity of the palate and/or alveolus and lip between 2003 and 2017 were investigated. All available medical documents were analyzed. The study group was divided into subgroups: 1) patients with isolated cleft palate (CP) and patients with a cleft palate with cleft lip and alveolus (CLP). 2) According to Veau's classification (I-IV), further subgroups were defined. Cleft width was measured using plaster cast models. RESULTS: TTS was performed in 55% of the patients (n = 43). Considering Veau's classification, TTS was conducted as follows: Veau I 65.2% (n = 15/23), Veau II 55.0% (n = 11/20), Veau III 47.6% (n = 10/21), and Veau IV 50.0% (n = 7/14). Cleft classifications, maxillary arch width, and absolute/relative cleft width had no statistical impact on TTS occurrence. Although no significant correlation could be found, patients in our study group with CP (Veau I and II) underwent TTS more often (60.5%, n = 26/43) than patients with CPL (Veau III and IV; 48.6%, n = 17/35) during a three-year follow-up. CONCLUSION: None of the cleft characteristics examined had a significant impact on the proportion of patients who received TTS. Nevertheless, patients with lower Veau classification and CP received tympanostomy tubes more often. Therefore, otolaryngologists and pediatricians treating children with cleft palate should maintain a high level of suspicion for chronic middle ear effusion, even in patients with small clefts. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:E2764-E2769, 2021.

Aplicabilidad del método Tanaka-Johnston para la estimación del diámetro mesiodistal de caninos y premolares en pacientes de 12-18 Años / Applicability of the Tanaka-Johnston method for the estimation of the mesiodistal diameter of canines and premolars in patients of 12-18 years old

El método Tanaka-Johnston es utilizado mundialmente para predecir el diámetro de caninos y premolares no erupcionados por la conveniencia de no necesitar tablas ni radiografías para su uso. Sin embargo, durante los últimos años investigadores de varios países han demostrado que al ser utilizado en una población diferente para la que fue diseñado, puede sobrestimar o subestimar los valores. En Cuba, donde el patrón facial de la población difiere del ideal para este método, ha sido muy empleado, pero prácticamente no existen estudios donde se valide la confiabilidad o exactitud de las predicciones de este. Por tanto, el objetivo de esta investigación es determinar la aplicabilidad del método Tanaka-Johnston para la estimación del diámetro mesiodistal de caninos y premolares en pacientes de 12-18 años. Se desarrolló un estudio descriptivo y transversal desde junio de 2019 hasta enero de 2020 con una población de 140 pacientes de ambos sexos de entre 12 y 18 años de Cuba. Se efectuaron las mediciones de los anchos mesiodistales de los incisivos inferiores, todos los caninos y premolares. Se realizaron distribuciones de frecuencia a las variables estudiadas y los resultados se presentaron en tablas estadísticas. Para comprobar la existencia de diferencias significativas se utilizó la prueba estadística t-Student. Los resultados principales obtenidos fueron que el método Tanaka-Johnston tiende a sobrestimar los valores para el sexo femenino y subestimarlos para el masculino, ambos entre los 0,2 y 0,3 mm, pero esta diferencia no resulta significativa. Se concluye que el método Tanaka-Johnston puede ser aplicado en la población estudiada para la predicción del ancho mesiodistal de caninos y premolares no erupcionados.

The Tanaka-Johnston method is used worldwide to predict the diameter of canines and premolars not erupted for the convenience of not needing boards or x-rays for use. However, in recent years researchers from several countries have shown that when used in a different population for which it was designed, it can overestimate or underestimate the values. In Cuba, where the facial pattern of the population differs from the ideal for this method, it has been highly used, but there are very few studies where the reliability or accuracy of the predictions of the same is validated. Therefore, the objective of this research is to determine the applicability of the Tanaka-Johnston method for estimating the mesiodistal diameter of canines and premolars in patients aged 12-18 years. A descriptive and cross-cutting study was conducted from June 2019 to January 2020 with a population of 140 patients of both sexes between 12 and 18 years of age from Cuba. Measurements were made of the mesiodistal widths of the lower incisors, all canines, and premolars. Frequency distributions were made to the variables studied and the results were presented in statistical tables. The t-Student statistical test was used to verify significant differences. The main results obtained were that the Tanaka-Johnston method tends to overestimate the values for the female sex and underestimate them for the male, both between 0,2 and 0,3 mm, but this difference is not significant. It is concluded that the Tanaka-Johnston method can be applied in the population studied for the prediction of the mesiodistal width of unerupted canines and premolars.

Anterior open bite and its relationship with dental arch dimensions and tongue position during swallowing and phonation in individuals aged 8-16 years: A retrospective case-control study.

OBJECTIVE: To determine the relationship between AOB and factors such as dental arch dimensions and tongue position during swallowing and phonation. MATERIAL AND METHODS: A case-control study was performed in two groups: 132 children with Anterior Open Bite (AOB) and 132 with normal vertical overbite (NVO), aged 8-16 years selected from the records taken by a previous study from five public schools. Dental arch dimensions were assessed through digitalized study models. Swallowing was evaluated using the Payne technique, and phoniatric assessment included an adaptation of the articulation test used to describe phonemes. STATISTICAL ANALYSIS: Chi-Square or Fisher's exact test for comparisons between qualitative variables and the Mann Whitney or T-student were applied to compare the dental arch dimensions according to bite type. A logistic regression model was applied to control the effect of confusion between independent variables and to describe its simultaneous effect on the type of bite. RESULTS: Intercanine, interpremolar and intermolar widths showed higher values in AOB patients with a mean deviation (MD) of 0.536 (P=0.031), 0.60 (P=0.043) and 1.15, (P<0.001) respectively. Distortions caused by tongue interposition and thrust, tongue protrusion during swallowing, mandibular arch intermolar width, total maxillary arch length, maxillary arch perimeter, and posterior arch depth accounted for 64.6% of AOB and allowed for correct predictions in 83.8% of the cases observed in the study population. CONCLUSIONS: A significant association between tongue position and function, as well as alterations such as tongue interposition and thrust during swallowing and phonation in individuals with AOB, were observed. There is a relationship between AOB and the presence of a wider mandibular arch and a narrower, longer, and deeper maxillary arch.

Intrauterine maxillary development and maxillary dental arch biometry: a fetal cadaver study.

INTRODUCTION: This study's goal was to determine normal maxillary development on fetal cadavers. MATERIALS AND METHODS: This study was carried out on 45 fetuses aged between the 17th - 40th weeks of gestation (24 male, 21 female). The distance between the widest left and right points of the maxillary dental arch (MDA) on the transverse plane, the distance of the papilla incisiva (PI) to the widest left and right points of the maxillary dental arch (MDAW), and the PI and posterior nasal spine (PNS) were measured. The average arch forms of the MDA were created according to trimester groups using the MATLAB program. The one-way ANOVA test was used to make a comparison between trimester groups, and ANOVA followed by post hoc analysis using the Bonferroni test was applied for comparisons. Pearson's correlation analysis was used for correlation analysis. RESULTS: The data in the present study did not differ between genders. In the comparison between trimester groups, we did not find any difference between the 3rd trimester and full-term groups only in the PI-MDAW measurement. Other parameters increased with age. In the correlation analysis, the measurement values by age showed a strong positive correlation. The MDAW exhibited the best correlation with age (rweek = 0.919). When the average MDA forms created using the MATLAB program were evaluated, it was observed that the PI-MDAW of the average MDA in the 3rd trimester and full-term intersected. CONCLUSIONS: This study provides a basis for a better understanding of fetal maxillary growth processes and can be useful to standardize the detection of malformations or intrauterine growth restrictions.

Valoración de las dimensiones del paladar y su relación con alteraciones verticales / Avaliação das dimensões do palato e sua relação com alterações verticais / Assessment of palate dimensions and its relation with vertical alterations

Objetivos: La presente investigación tuvo como objetivo establecer la correlación entre la presencia de maloclusiones a nivel vertical con el índice del paladar y con la altura palatina. Materiales y Métodos: Estudio de tipo transversal. La población de estudio fue conformada por 134 modelos de yeso con dentición mixta, 81 mujeres y 53 hombres, seleccionados por conveniencia y obtenidos desde el 2014 hasta el 2018 del área de clínica de odontopediatría y ortodoncia en la Escuela Nacional de Estudios Superiores Unidad León. La muestra de estudio fue dividida en 3 categorías según la oclusión; mordida abierta (37), mordida profunda (32) y normoclusión (65). Se realizaron mediciones del ancho intermolar y altura del paladar con el uso de un calibrador digital, posteriormente se obtuvo el índice del paladar y se correlacionó con los parámetros expuestos por Korkhaus mediante la prueba estadística de Spearman. Resultados: La prueba estadística de Spearman refleja que no hay correlación entre la magnitud de los valores del índice del paladar propuestos por Korkhaus con la presencia de maloclusiones a nivel vertical. De igual manera las pruebas estadísticas indican que no existe correlación notable entre la altura del paladar y la oclusión en relación vertical. Conclusiones: El resultado obtenido al usar el índice del paladar no fue capaz de corresponder a los parámetros propuestos por Korkhaus como normales, posiblemente al ser usado durante la etapa de la dentición mixta pues durante este periodo suceden cambios constantes relacionados al crecimiento.

Objetivos: Os objetivos a presente investigação buscou valor uma correlação entre a presença de más oclusões em nível vertical com o índice do palato e com a altura palatina. Materiais e Métodos: Estudo do tipo transversal. A população do estudo foi composta por 134 modelos de gesso com dentição mista, 81 mulheres e 53 homens, selecionados por conveniência e obtidos de 2014 a 2018 na área de Odontopediatria e Ortodontia na Escola Nacional de Ensino Superior Unidade de León. A amostra do estudo foi dividida em 3 categorias de acordo com a oclusão; mordida aberta (37), mordida profunda (32) e normoclusão (65). A medida da largura intermolar e da altura do palato foi feita com o uso de um paquímetro digital, o índice de palato foi posteriormente obtido e relacionado aos parâmetros expostos por Korkhaus por meio do teste estatístico de Spearman. Resultados: O teste estatístico de Spearman mostra que não há correlação entre a magnitude dos valores do índice de palato proposta por Korkhaus e a presença de más oclusões verticais. Da mesma forma, os testes estatísticos indicam que não há correlação notável entre a altura do palato e a oclusão na relação vertical. Conclusões: O resultado obtido com o uso do índice de palato não foi capaz de corresponder aos parâmetros propostos por Korkhaus como normais, possivelmente quando usado durante o estágio de dentição mista, porque durante este período há mudanças constantes relacionadas ao crescimento

Purpose: The aim of the present study is to assess the relation between vertical malocclusions with palatal index and palatal height. Materials and Methods: Transversal study. The sample consisted in 134 stone models within mixed dentition, 81 females and 53 males, they were convenience selected and obtained from the pediatric and orthodontic dentistry medical center at the National School for Superior Studies Unit León since 2014 to 2018. The stone models were divided into three categories according to their kind of occlusion: open bite (37), deep bite (32) and normal bite (65). Palatal width and height were measure by using a digital caliper. Subsequently the palatal index was obtained and it was related with the parameters exposed by Korkhaus using the Spearman statistical test. Results: The Spearman statistical test indicated there is no a clearly relationship between palatal index values exposed by Korkhaus with the presence of vertical malocclusions and in the same way there is no a relationship between palatal height and vertical malocclusions.Conclusions: The result obtained by using the palatal index was no able to indicate an agreement with Korkhaus parameters. Probably this disagreement was due to the constant changes that occur during the period of the mixed dentition.

A randomized clinical trial to assess the sagittal effects of Transforce transverse appliance (TTA) and NiTi palatal expander (NPE) on skeletal class II malocclusion in growing patients during retention phase - A cephalometric study using a historical control group.

OBJECTIVES: To evaluate and compare the skeletal changes during the retention period after expansion with "Transforce Transverse lingual or palatal Appliance®" (TTA) and "NiTi Palatal Expander®" (NPE) in growing subjects with class II division 1 malocclusion and to compare these changes with a matched historical control. SUBJECTS AND METHODS: A unicentric two arm, parallel randomized clinical trial with additional historical control group was conducted over a period of six years. The subjects in the age group of 9-13 years were screened and recruited as they reported. The inclusion criteria were: late mixed/early permanent dentition, class II or end on molar relationship, posterior transverse inter-arch discrepancy 4-8mm, overjet≥5mm, cephalometrically ANB>4° and CVMI stage CS2-CS3. Subjects were randomly allocated to two study groups (SG), TTA and NPE using block randomization. Appliances in both SG were managed and followed by a single clinician with equal standards of care. The lateral cephalograms in digital form were obtained at the beginning of the treatment (T1), post-expansion (T2) and after ten months retention period (T3). Linear positional change>1mm and angular change>0.75° were considered as a clinically significant change. Due to the ethical reasons a historical control of ten patients (CG) comparable to the SG for age and inclusion criteria was used to rule out the growth changes on serial lateral cephalograms. All Cephalometric measurements were done by a single operator blinded for the group allocation. Operator's measurement error was estimated. The study was single-blinded in regard to statistical analysis. Inter-group comparisons between SG were made by using an unpaired Student's t-test. ANOVA with post-hoc analysis was used for comparison among the study and control groups. RESULTS: A total of 36 subjects were recruited, 18 in each SG. Average time required to achieve the desired expansion in the TTA and NPE group was 13.6 weeks and 9.8 weeks respectively. The TTA group showed significant increase in SNB (1.54±0.33°) when compared with the control group (0.53±0.37°) and with the NPE group (0.74±0.29°) (P<0.0001). Significant differences were observed when post-retention changes in SNB, ANB, Wits appraisal, and N perpendicular to Pogonion, were compared among the three groups (ANOVA, P<0.0001). Tukey's multiple comparison showed that these mandibular sagittal changes were significantly greater in the TTA group than in NPE and the control group (P=<0.007, Bonferroni corrected value). CONCLUSION: Cephalometrically significant sagittal advancement of mandible took place after expansion with TTA and NPE compared to untreated control. TTA appears to be more efficient for the sagittal positional changes than the NPE. Additional studies with larger samples are warranted to elucidate individual variations in skeletal response to the expansion protocol with these appliances.

Influence of the palatine tonsil grade on the morphology of the maxillary and mandibular dental arches / Influencia del grado de las tonsilas palatinas en la morfología de los arcos dentales maxilar y mandibular

SUMMARY: Enlarged palatine tonsils and adenoids are thought to cause obstruction of the upper airway, triggering changes in breathing patterns, which in turn lead to dentofacial alterations, including malocclusions. The object of the present study was to correlate the size (grade) of the palatine tonsil with measurements of the maxillary and mandibular dental arches in children. This was an observational cross-sectional study carried out in 35 children aged between 6 and 11 years. The inter- and intra-arch parameters were measured (horizontal, vertical and sagittal analyses) by making plastercasts and then taking measurements with callipers. The tonsil size was classified in 5 grades from 0-4, using the Brodsky tonsil grading scale. The researcher was calibrated prior to carrying out the measurements. Pearson's chi-squared test was used and Pearson's correlation coefficient was calculated. The SPSS v.22.0 software was used, with a significance threshold of 5 %. Six patients were classified as grade 1, sixteen grade 2, eleven grade 3, two grade 4 and none of the patients presented grade 0.A low positive association was found between tonsil grade and the total length of the mandibular arch, a very low positive association between tonsil grade and maxillary inter-first premolar distance, total length of the maxillary arch and depth of the palatine recess.A very low negative association was found for tonsil grade and overjet, overbite, mandibular inter-permanent first molar distance, mandibular inter-first premolar distance, and mandibular and maxillary intercanine widths. No statistically significant correlation was observed for any of the measurements. No association was found between the tonsil grade and Angle's Classification, canine relationship, overjet and overbite. According to the results of this study there is no significant correlation between the dental arches and the tonsil grade.

RESUMEN: Se ha considerado que el grado del tamaño de las tonsilas palatinas y los adenoides pueden ser factores que generan obstrucción de la vía aérea superior, desencadenando cambios en el patrón de respiración, lo que provoca alteraciones dentofaciales, entre ellas, maloclusiones. El objetivo del presente estudio fue correlacionar el grado tonsilar palatino con medidas de los arcos dentales maxilar y mandibular en niños. Se realizó un estudio observacional de corte transversal. Fueron incluidos 35 niños entre 6 y 11 años de edad. Fueron medidos parámetros interarco e intra-arco (análisis transversal, vertical, sagital). Para eso fueron tomados modelos de yeso y luego las medidas fueron realizadas con un caliper. El grado tonsilar fue clasificado en 5 grados (0-5), de acuerdo a la escala de graduación de Brodsky. Para la realización de las mediciones el evaluador fue previamente calibrado. Se realizó la prueba Chi-cuadrado de Pearson, y coefi- ciente de correlación de Pearson. Se utilizó el software SPSS 22.0, considerándose umbral de significación de 5 %. Seis pacientes fueron clasificados en grado 1, dieciséis grado 2, once grado 3, dos grado 4 y ningún paciente presentó grado 0. Se encontró una asociación positiva baja entre grado tonsilar y la longitud total del arco mandibular, positiva muy baja entre grado tonsilar y distancia inter-primer premolar maxilar, longitud total del arco maxilar y profundidad de la bóveda palatina. Una asociación negativa muy baja fue encontrada para el grado tonsilar y overjet, overbite, distancia inter-primer molar permanente mandibular, distancia inter- primer premolar mandibular, ancho intercanino mandibular y maxilar. Se observó ausencia de correlación estadísticamente significativa para todas las medidas. No se encontró asociación entre el grado tonsilar y clase molar de Angle, relación canina, overjet y overbite. Según los resultados de este estudio no se aprecia una correlación significativa entre los arcos dentales y el grado tonsilar.

The impact of playing wind musical instruments on the dental arch dimensions in a male west african population.

BACKGROUND: Dental arch dimensions are important considerations in orthodontic treatment planning and monitoring. OBJECTIVE: This study aimed to compare the dental arch dimensions in wind and non-wind instrument players (WIP and non-WIP). METHODS: This was a cross-sectional study which compared a group of 50 male subjects aged 18-45 years that had been playing wind instruments for a minimum of 2 years with a control group matched for age in the same environment. The arch dimensions were assessed for both groups by measuring their dental casts using a digital caliper. Data was analyzed using statistical Software Package for Social Sciences (SPSS Inc, Chicago, IL) version 17. Statistical significance level was set at P < 0.05. RESULTS: The mean number of years of playing wind instrument among the WIP was 9.26 ± 6.21 years. All the maxillary arch dimensions were larger in the WIP group except for the palatal depth while the mandibular arch parameters in the non-WIP group were larger than the WIP group except the mandibular arch length. The differences were not statistically significant (P > 0.05). The mean maxillary inter-canine width (37.48 ± 1.12 mm), inter-molar width (57.27 ± 1.99 mm), arch length (29.80 ± 2.2.09 mm), and palatal depth (22.21 ± 2.33 mm) for class B instrument (Saxophone and clarinet) players were larger than either the class A instrument (Trumpet and trombone) players or the non-WIP group. These differences were not statistically significant (P > 0.05). CONCLUSIONS: Playing a wind instrument as well as the type of instrument played, duration, and frequency of play did not significantly affect dental arch dimensions.

Age at first molar emergence in Pan troglodytes verus and variation in the timing of molar emergence among free-living chimpanzees.

Age at lower first molar (M1) emergence is a commonly used proxy for inferring life-history scheduling in fossil primates, but its utility is dependent on knowing to what extent extant populations vary in this datum and how this variation correlates with the scheduling of life-history variables. Here, we address the first of these issues among extant chimpanzees. While age at M1 emergence has been documented in several live individuals from the Kanyawara population of Pan troglodytes schweinfurthii in Uganda, it has been estimated for only one individual of Pan troglodytes verus, based on a deceased animal from the Taï Forest in Côte d'Ivoire. To further explore interpopulation variation in this variable in chimpanzees, and using dental histology, we calculated ages at death for two wild-shot individuals of P. t. verus with erupting M1, both collected in Liberia during the mid-1950s, and estimated ages at M1 emergence from the ages at death. The overall range for these two individuals is ∼4.2-4.6 yr, compared with an age of ∼3.7 yr for the individual from the Taï Forest, and <2.5-3.3 yr for the several individuals of P. t. schweinfurthii. While the absolute range of ∼2 yr in these samples combined is little greater than in captive chimpanzees, the disparity between the samples of P. t. schweinfurthii and P. t. verus is striking, although it cannot be determined if this disparity represents a subspecies difference or simply population differences expressed in two different subspecies. While life-history data are unavailable for the population to which the Liberian chimpanzees belonged, the difference in M1 emergence ages between these individuals and those from Kanyawara still suggests caution when attempting even broad life-history inference in fossil apes and hominins based on age at M1 emergence.

Differences in dental arch characteristics between genders in patients with suspected condylar hyperplasia in a North Sumatra subpopulation: a cross-sectional study.

Background: Condylar Hyperplasia (CH) is a self-limiting mandibular condyle disorder that shows asymmetry progress conjunction with associated occlusal changes as long as condylar growth is still active and leads to facial asymmetry. This study aimed to evaluate dental arches by analyzing dental arch asymmetry and form in orthodontic patients with CH in a North Sumatra subpopulation. Methods: This is a retrospective study of suspected CH patient's clinical records who sought for the initial orthodontic treatment between January 2015 to March 2019. Patient with facial asymmetry (based on photography, posterior cross bite and midline deviation), positive temporomandibular joint disorder in functional analysis, and no history of facial trauma were included in the study. Dental arch asymmetry was based on the measurement of dental midline deviation, canine tip in the dental arch, distance of the upper canines from the palatal suture, and inter canine distance. The evaluation of dental arch was achieved by comparing arch width and length. Results: There was a significant difference (p<0.05) of upper canine distance from the palatal suture in female patients when evaluating upper dental arch asymmetry. There was a moderate correlation (r=0.379) in midline deviation between upper and lower dental arch. The dimension and dental arch form was mid and flat, and there was moderate correlation (r=0.448) between the upper and lower dental arch form in these CH patients. Conclusion: The evaluation of dental arch symmetry and arch form showed asymmetric occlusal characteristics in orthodontics patient with CH in North Sumatera subpopulation. In treating these patients, we recommend the plaster cast evaluation as essential and routine procedure in order to understand the complexity of occlusal change due to active growth of condylar and limitation in radiography evaluation.

Dentofacial biometry as a discriminant factor in the identification of remote Amazon indigenous populations.

INTRODUCTION: This study aimed to examine the role of dentofacial morphology in discriminating semi-isolated indigenous groups. These populations present a similar pattern of dietary habits. Studies in human genetics have reported a large intertribal genetic distance and low intratribal variation. METHODS: This study was conducted following the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. Face dimensions were measured through facial photogrammetry, and dental arches and tooth size were evaluated using plaster models. A total of 98 subjects in the permanent dentition and belonging to 4 indigenous groups were analyzed: Arara-Iriri (n = 20), Arara-Laranjal (n = 33), Assurini (n = 25), and Xicrin-Kayapó (n = 20). The random and systematic errors were verified using the Dahlberg formula and the intraclass correlation coefficient (ICC), respectively. In order to evaluate the discrimination of the variables to identify the indigenous groups, a discriminant analysis was performed (P <0.05). RESULTS: A small causal error (Dahlberg, 0.13-1.81) and excellent replicability (ICC, 0.75-0.99) for face dimensions as well as for models (Dahlberg, 0.10-0.68; ICC, 0.94-0.99) were observed. The discriminant analysis allowed the identification of 4 populations by facial and dental arch dimensions and tooth size. Dentofacial biometry revealed an accuracy of 98% for females and 100% for males, which confirms a high intragroup homogeneity and considerable intergroup heterogeneity for dentofacial features. CONCLUSIONS: Biometric measurements of the human face added with tooth size and dental arch dimensions are very useful to identify remote indigenous populations with high accuracy. Supported by previous studies in human genetics, these findings reinforce the role of genetic variation in the determination of dentofacial features.

Comparing the trueness of seven intraoral scanners and a physical impression on dentate human maxilla by a novel method.

BACKGROUNDS: Intraoral scanner (IOS) accuracy is commonly evaluated using full-arch surface comparison, which fails to take into consideration the starting position of the scanning (scan origin). Previously a novel method was developed, which takes into account the scan origin and calculates the deviation of predefined identical points between references and test models. This method may reveal the error caused by stitching individual images during intraoral scan. This study aimed to validate the novel method by comparing the trueness of seven IOSs (Element 1, Element 2, Emerald, Omnicam, Planscan, Trios 3, CS 3600) to a physical impression digitized by laboratory scanner which lacks linear stitching problems. METHODS: Digital test models of a dentate human cadaver maxilla were made by IOSs and by laboratory scanner after polyvinylsiloxane impression. All scans started on the occlusal surface of the tooth #15 (universal notation, scan origin) and finished at tooth #2. The reference model and test models were superimposed at the scan origin in GOM Inspect software. Deviations were measured between identical points on three different axes, and the complex 3D deviation was calculated. The effect of scanners, tooth, and axis was statistically analyzed by the generalized linear mixed model. RESULTS: The deviation gradually increased as the distance from scan origin increased for the IOSs but not for the physical impression. The highest deviation occurred mostly at the apico-coronal axis for the IOSs. The mean deviation of the physical impression (53 ± 2 µm) was not significantly different from the Trios 3 (156 ± 8 µm) and CS 3600 (365 ± 29 µm), but it was significantly lower than the values of Element 1 (531 ± 26 µm), Element 2 (246 ± 11 µm), Emerald (317 ± 13 µm), Omnicam (174 ± 11 µm), Planscan (903 ± 49 µm). CONCLUSIONS: The physical impression was superior compared to the IOSs on dentate full-arch of human cadaver. The novel method could reveal the stitching error of IOSs, which may partly be caused by the difficulties in depth measurement.

Long term skeletal and dental changes between tooth-anchored versus Dresden bone-anchored rapid maxillary expansion using CBCT images in adolescents: Randomized clinical trial.

OBJECTIVE: The aim of this study was to determine long-term skeletal and dental changes in tooth-anchored versus Dresden bone-anchored rapid maxillary expansion using CBCT images in adolescents. MATERIALS AND METHODS: In all, 29 adolescent patients (11-17 years of age) needing skeletal expansion were randomly allocated to two different groups treated by either a Dresden bone-anchored expander or a conventional hyrax expander. Patients included did not have previous orthodontic treatment, were non-syndromic and had all teeth present in mouth. CBCT images were taken before expansion and two or more years after expansion. An independent T-test was used to determine the statistical significance between treatment groups and paired T-test was used to compare the results before and after expansion in each group. RESULTS: Neither treatment group showed overall long-term different skeletal and dental changes in the transverse, anterior-posterior and vertical planes (P<0.05). Both treatment groups showed mild asymmetric skeletal expansion, but these were clinically insignificant. CONCLUSIONS: Both expanders had similar skeletal and dental results. The greatest changes were in the transverse plane. Changes in vertical and anterior-posterior were negligible.

Transverse, vertical, and anterior-posterior changes between tooth-anchored versus Dresden bone-anchored rapid maxillary expansion 6 months post-expansion: A CBCT randomized controlled clinical trial.

OBJECTIVE: The main aim of this randomized clinical trial was to determine 3 dimensional skeletal and dental changes six months after the use of bone-anchored versus tooth-anchored rapid maxillary expanders in adolescents. The secondary aim was to determine the symmetrical or asymmetrical expansion pattern between both appliances. MATERIALS AND METHODS: Fifty adolescents with skeletally constricted maxilla (mean age 13-14 years) were randomly assigned into: Dresden B-RME, Hyrax T-RME, or untreated control groups. CBCT scans were taken at initial and expander removal (6 months). Three-dimensional references and treatment landmarks were identified. Orthogonal distances were calculated from those landmarks. The main outcome was to compare skeletal and dental changes in each group and the secondary outcome was to verify if these changes were symmetric or not. Data was analysed using descriptive statistics and repeated measure MANCOVA and MANOVA. RESULTS: Both treatment groups showed significant skeletal and dental expansion compared to controls. T-RME group had greater mean inter-molar crown expansion (5.66mm) than the B-RME group (4.17mm). Both T-RME and B-RME groups showed significant skeletal maxillary expansion compared to controls (mean 1.27mm and 1.31mm respectively, both p<0.01), although no significant difference was found between both appliances. B-RME group showed a lower ratio of dental to skeletal expansion than T-RME group. T-RME showed a symmetrical expansion pattern, whereas the B-RME showed an asymmetrical pattern relative to mid-sagittal plane. The extent of molar crown expansion was 1.84mm greater on the TAD-side compared to the Implant-side. T-RME group showed significant anterior movement of the maxillary first premolar and molar (1.5mm, p<0.05), and vertical dental extrusion (1.8mm). No significant dental vertical or anterior-posterior changes were noted in the B-RME group. CONCLUSIONS: T-RME and B-RME produced similar amounts of skeletal expansion. B-RME group produced a lower component of dental expansion. Due to the Dresden B-RME configuration, asymmetrical expansion was noted.

Palatoscopy and odontometrics' potential role in sex determination among an adult Egyptian population sample: A pilot study.

Background: Sex determination is the first step in personal identification in the forensic field. This study aimed to evaluate sexual dimorphism by using palatal rugae pattern and odontometrics, construct an Egyptian equation for sex determination using the discriminant function analysis. Participants and methods: The study sample included 200 participants of both sexes. Maxillary arch impressions were taken with alginate impression material using stainless steel impression tray. Identification and measurements were done to study the palatal rugae pattern, dental arch dimensions, and maxillary canine. Results: There was a highly statistically significant difference between males and females with higher male values regarding the total palatal rugae number, wavy rugae number, primary rugae number, arch length, width, maxillary canine right width, maxillary canine left width, intercanine distance, and maxillary canine right index while there was a highly statistically significant difference with higher female value regarding the straight rugae numbers. Four Egyptian equations were constructed using discriminant function analysis to determine the sex of an unidentified person. Conclusions: Palatal rugae pattern, dental arch dimensions, and maxillary canine index can be considered as useful tools for sex determination in the forensic field.