Validación y Comparación de un Nuevo Método para Predecir el Ancho Mesiodistal de Caninos y Premolares no Erupcionados en una Población Chilena de la Región de Valparaíso, Chile

Uno de los principales problemas durante la dentición mixta es la determinación de la futura discrepancia entre tamaño dentario y el espacio disponible. Para predecir el ancho mesiodistal de los dientes permanentes no erupcionados se han introducido diferentes métodos de análisis. Objetivo: El propósito de este estudio fue comparar el método Tanaka-Johnston con una nueva ecuación de regresión para predecir el ancho mesiodistal de caninos y premolares permanentes no erupcionados en una población de la región de Valparaíso, Chile. Material y método: Este estudio fue realizado en la Facultad de Odontología de la Universidad de Valparaíso, desde octubre de 2022 a junio de 2023 (8 meses), la muestra estuvo compuesta por 202 modelos de estudio del departamento de ortodoncia (91 hombres y 111 mujeres) en el rango de edad de 11 -20 años. Resultados: Se demostró que el método elaborado por Lara-Sandoval presenta mayor fiabilidad respecto a las medidas mesiodistales reales de los pacientes (ICC 0,773 para maxilar y 0,762 para mandíbula), en comparación con el método de Tanaka-Johnston (ICC 0,665 para maxilar y 0,623 para mandíbula). No existen diferencias significativas entre los valores reales y el método de Lara-Sandoval. Conclusión: El método de Lara-Sandoval es mejor que el propuesto por Tanaka-Johnston para determinar el ancho mesiodistal de caninos y premolares para esta muestra. Es necesario validar este método en otras regiones del país para ser utilizado con mayor seguridad que el ya existente como método estándar nacional.

One of the main orthodontic problems in mixed dentition is the determination of future tooth and size arch discrepancy. In order to predict the mesiodistal widths of unerupted permanent teeth different methods of analyses have been introduced. The aim of this study is to compare the Tanaka-Johnston analysis with a new regressive equation to predict the mesiodistal width of unerupted permanent canines and premolars in a Chilean population sample, from Valparaíso region. This study was conducted at the Universidad de Valparaíso Dental Faculty, from october 2022 to june 2023 (8 months), and the sample comprised historical dental casts from 202 patients (91 boys and 111 girls) in the age range of 11-20 from the orthodontics department. All the patients are from the Valparaíso region, Chile. The results show that the predictions of the new regressive equation method are closer to the actual mesiodistal measurements of the patients (ICC 0,773 for maxilla and 0,762 for mandible), compared to the Tanaka- Johnston method (ICC 0,665 for maxilla and 0,623 for mandible). There are no significant differences between the real values and the Lara-Sandoval method. Lara-Sandoval method is better than the one proposed by Tanaka-Johnston to determine the mesiodistal width of canines and premolars in this sample population. It is necessary to validate this method in other regions of the country to be used with greater security than the ones that already exists as a national standard method.

Estimation of human somatype using inter-canine and inter-premolar distances of the maxillary arch.

Context: The establishment of a correlation between tooth dimensions and body size is crucial within the realm of forensic odontology. While numerous investigations have focused on the association between tooth morphology or width and stature, limited reports exist regarding the correlation between overall body structure or build and odontogenic parameters. This study focuses on finding a correlation between inter-arch dimensions and the body build of an individual. Aims: This study aimed to examine the potential correlation between an individual's somatotype (body build) and the measurements of inter-canine and inter-premolar maxillary arch widths. Study Settings: Dayananda Sagar College of Dental Sciences. Study Design: A cross-sectional study. Methods and Material: The sample size of the study was 153 individuals aged 18-25 years. Impressions for the maxillary arch were taken, study models were made and inter-arch measurements were taken using a digital Vernier calliper. For body build measurements, Heath-Carter somatotype measuring technique was used. The collected data were entered into an Excel sheet, and statistical analysis was done. Statistical Analysis Used: Principal component analysis. Results: On using principal component analysis, it was seen that there exists no correlation between body build of an individual when compared to inter-canine and inter-premolar distances. Conclusions: While no positive correlation has been seen between the odontometric parameters and specific body type, it can be argued that this can be due to the cited limitations of the study. Hence, we conclude with the note that a more detailed study would offer more viable and credible results.

Application of Moyer's mixed dentition analysis and establishing probability tables in a sample of Pakistani population.

Objective: To assess the congruity of Moyers' dental analysis in Pakistani individuals and to make tables foreseeing the size of non-erupted permanent premolars and canines in children. Methods: A cross-sectional study was conducted at Orthodontics Department of Armed Forces Institute of Dentistry (AFID) Rawalpindi, Pakistan. This was conducted from January 2020 to December 2021 and included mixed dentition subjects' casts. Mesiodistal widths (MDW) of the permanent dentition were estimated and contrasted with the anticipated values that emerged from the Moyer's mixed dentition examination. Students t-test, simple linear regression and Pearson correlation coefficient examination were utilized for statistical correlation. All data was gathered utilizing an electronic digital caliper and further investigated through IBM SPSS Statistics 24. Results: Dental casts of the 258 subjects, 106 (41%) males and 152 (58.9%) females with the ages ranging 15.825±2.95 years were analyzed. Tooth size contrasts were significant (p <0.05) which was noticed in comparison to Moyer's predictive table. This demonstrates a bigger tooth size in young men than in young ladies. New probability tables were created through linear regression equations for our population. Conclusion: Moyer's prediction cannot be applied to the Pakistani population. Mandibular incisors in addition to maxillary first molars are superior in prediction for the size assessment of canines and premolars (cp) that are unerupted in males and upper arch only in females. Another noteworthy conclusion is that in our study sample, in lower arch of females, the width of mandibular molars with mandibular incisors predicts better.

A study to estimate tooth size discrepancy values specific to Saudi orthodontic patients: A systematic review and meta-analysis.

Objective: This study aimed to establish intermaxillary tooth size ratios (overall index (OI) and anterior index (AI)) for normal occlusion and different Angle's malocclusions specific to the Saudi population and compare them to Bolton's values, which were specific to Americans. Methods: The Saudi Digital Library, PubMed, Web of Science, Cochrane Library, Scopus, and Embase were searched systematically to acquire articles which reported OI and AI for Saudi patients; inclusion and exclusion criteria were applied. Data, including author's name, publication year, city, measurement technique, number of subjects, type of occlusion, means, and standard deviations, were extracted and sorted. To assess the methodological quality of the included studies, The National Heart, Lung, and Blood Institute Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies was utilized. Results: Of the 1473 articles, eight met the inclusion criteria and were included in the meta-analysis. Values for normal occlusion and Bolton's values were not significantly different. All malocclusion classes showed significant differences in the overall OI and AI values compared with Bolton's original values and values for normal occlusion, but they did not differ from each other. Gender showed an effect only on the OI ratio for Class III malocclusion. Conclusions: Bolton's original values can be used in Saudi patients only with normal occlusion. For cases with any Angle's malocclusion, we recommend using an AI value of 79.08 (±3.4) for both genders. Classes I and II, regardless of gender, have the same OI value of 92.51 (±2.82). For Class III, values of 91.97 (±2.4) for females and 93.13 (±2.6) for males can be used.

Few dental indices in modern Bulgarian population from southern Bulgaria.

AIM: The aim of the present study is to evaluate the reduction of the distal teeth towards the medial ones in one functional dental group in southern Bulgarian population. MATERIALS AND METHODS: The study included 232 Bulgarians aged 20-40 years. Mesiodistal dimensions of the teeth were measured by Dentistry Sliding Vernier Caliper and analyzed with SPSS 23.0. Four interdental indices were calculated: inter-incisive, premolar, upper, and lower molar indices. RESULTS: We found a decrease in the percentage ratio of the lateral to the central incisors of people from the Bulgarian population compared to those dating from the Eneolithic period on the territory of Bulgaria. Furthermore, we found a reduction in the percentage ratio of the upper and lower second molars compared to the first ones. The biggest reduction in the percentage ratio (more than 6%) was found in the lower second premolars compared to the first ones, which is characteristic for southern Bulgarians. CONCLUSION: There was a dental reduction in all the distal members compared to the medial ones participating in one morphological dental group. As a result, we think that interdental indices can be used for explaining historical, cultural, and biological macro and microevolutionary processes and thus for understanding the origin, formation, contacts, and migration pathways of the different populations leading to ethnic variation of humanity. Therefore, they can be a reliable source of information in physiological anthropology.

Evaluation and comparison of linear and diagonal odontometry of first molars as a tool for gender discrimination; assessed in a population from Maharashtra.

Background: Linear odontometry is customarily used in gender determination which can pose difficulties in cases of tooth decay, attrition since they mainly involve the proximal surfaces. Objectives: The present cross-sectional observation study, estimated the efficacy of alternative measurements, that is, diagonal measurements and cervical measurements in gender determination in comparison to routine odontometry. Material and Methods: A total of 200 dental cast models (upper and lower) of 100 individuals (50 male and 50 female) from Maharashtra state were included. Results: Univariate discriminant function analysis showed that, in maxillary molars, MD width gave the highest gender dimorphism of 64%, followed by BL with 62%. In the mandibular teeth, MD gave an accuracy of 75% followed by MB-DL with 73%. Multivariate logistic regression analysis showed that overall diagonal and linear measurements gave the highest dimorphism of 81% with 80% correctly identified as females and 82% as males. The mandibular MD, BL and MB-DL gave an accuracy of 79% with 78% corrected identified as females and 80% correctly identified as males. Mandibular ML-DB and Cervical DB-CML together gave an accuracy of 77% and mandibular MD with75%. Conclusion: Thus, the study proves that diagonal measurements give almost equivalent or better results than linear measurements in gender determination.

Sexual Dimorphism in Teeth Dimension and Arch Perimeter of Individuals of Four Ethnic Groups of Northeastern India.

Objectives There is a disparity between males and females when it comes to size and appearance. In forensic and anthropological investigations, it is crucial to identify an unknown individual's gender, and it is possible to discern individual differences based on differences in dental features among populations. For identifying individuals, tooth dimensions are an effective, simple, and low-cost means of determining sex. Based on dental casts, this study aims to assess sexual dimorphism among four ethnic tribes of Northeast India using the mesiodistal (MD) dimension of canines and arch perimeter (AP) of the upper and lower jaws. Methods In each of the four ethnic groups studied, 50 males and 50 females with dental casts were measured in millimetres for the MD dimension of canines and AP of the upper and lower jaws. SPSS version 20 (IBM Corp., Armonk, NY) was used to analyze the data based on Student's t-test, considering a p-value of <0.05 as significant. Results Males had significantly larger MD dimensions of canines in the maxillary and mandibular jaws (p-value<0.05). The AP of both maxilla and mandible are higher in males than females in all four ethnic groups. However, the difference between the two genders for the AP of the maxilla is statistically significant only in Meitei and Singpho groups (p-value<0.05). In the case of the mandibular jaw, the AP was significantly lower in females in all four ethnic groups (p-value<0.05). Conclusion Significant sexual dimorphism exists among the individuals in the four ethnic group populations. The MD dimension and AP are essential to establish sexual dimorphism among populations. The MD dimension of the maxillary and mandibular canine and AP showed significant sexual dimorphism in the present study among all four ethnic groups.

Artificial neural network model for predicting sex using dental and orthodontic measurements.

Objective: To investigate sex-specific correlations between the dimensions of permanent canines and the anterior Bolton ratio and to construct a statistical model capable of identifying the sex of an unknown subject. Methods: Odontometric data were collected from 121 plaster study models derived from Caucasian orthodontic patients aged 12-17 years at the pretreatment stage by measuring the dimensions of the permanent canines and Bolton's anterior ratio. Sixteen variables were collected for each subject: 12 dimensions of the permanent canines, sex, age, anterior Bolton ratio, and Angle's classification. Data were analyzed using inferential statistics, principal component analysis, and artificial neural network modeling. Results: Sex-specific differences were identified in all odontometric variables, and an artificial neural network model was prepared that used odontometric variables for predicting the sex of the participants with an accuracy of > 80%. This model can be applied for forensic purposes, and its accuracy can be further improved by adding data collected from new subjects or adding new variables for existing subjects. The improvement in the accuracy of the model was demonstrated by an increase in the percentage of accurate predictions from 72.0-78.1% to 77.8-85.7% after the anterior Bolton ratio and age were added. Conclusions: The described artificial neural network model combines forensic dentistry and orthodontics to improve subject recognition by expanding the initial space of odontometric variables and adding orthodontic parameters.

Computed tomography assessment of hypodontia and crown size in hemifacial microsomia.

OBJECTIVE: Our aims were to assess the prevalence of hypodontia in unilateral hemifacial microsomia (HFM), and to compare tooth (crown) size between affected and unaffected sides. DESIGN: In a retrospective cross-sectional study of South Australians, computed tomography (CT) scans were used to assess hypodontia and crown size (mesiodistal length, buccolingual width and crown height). The inclusion criteria were the absence of other congenital anomalies and the availability of CT scans. The exclusion criteria were the lack of extraction history or reproducible landmarks for morphometric assessment. The final sample comprised 41 participants in both dentitions, including 32 children and 9 adults (median age 13.9 years, range 0.4 - 47.6 years; 19 males and 22 females). Hypodontia was assessed in all participants, and the permanent crown size in 30 (73.2%) participants. Linear mixed-effects models were performed to determine if crown size was significantly different between the two sides, controlling for sex, HFM severity, and tooth and jaw type. RESULTS: Hypodontia occurred in none of the participants in the primary dentition, but in 6/30 (20%) participants in the permanent dentition (3/30 each on the affected and unaffected sides). There was no significant difference in the mean crown dimensions between the two sides, but the crown size was larger in males (p < 0.05), except for mesiodistal length, and became progressively smaller with increased HFM severity (p < 0.05). CONCLUSIONS: Hypodontia spared the primary dentition but featured prominently in the permanent dentition. The permanent crown dimensions were unaltered between the two sides.

The relationship of tooth crown dimensions between first molar and central incisor in maxilla.

The purpose of this study was to investigate a correlation between the cusp dimensions of the first molar and mesiodistal crown diameters of the central incisors in the maxilla. The study materials were composed of dental casts from 29 modern Japanese female subjects with a mean age of 20 years and 8 months. The mesiodistal crown diameters of the maxillary central incisors were measured. The mesiodistal and bucco-lingual crown diameters and the cusp diameters of the maxillary first molars, such as the paracone, metacone, protocone, and hypocone, were also measured. The crown areas and indices of the first molars were calculated. The Spearman's single rank correlation coefficients between the mean values for the crown dimensions of the first molars and the mesiodistal crown diameters of the central incisors were calculated. The hypocone cusp diameter and the hypocone index were the largest compared to those of the paracone, protocone, and metacone cusps. The bucco-lingual diameter and hypocone cusp diameter of the first molars positively correlated with the mesiodistal crown diameters of the central incisors on the same sides. There were positive correlations between the hypocone index of the first molars and the mesiodistal crown diameters of the central incisors. Based on the results, if a large hypocone is observed in eruption of the maxillary first molars, it will be predictable that of the mesiodistal crown diameter of the maxillary central incisor large.

Crown dimensions of Malay deciduous teeth: Sex dimorphism and tooth size in Asia.

OBJECTIVE: This study documents deciduous tooth crown dimensions and sex dimorphism in modern Malay children of Indonesia. Comparisons are made with living and prehistoric East and South Asians to better understand tooth size variation in space and through time. DESIGN: Measurements of the dental crown were made with a Mitutoyo digimatic caliper, interfaced with a Dell laptop, running Microsoft Excel (2003). Buccolingual (BL) measurements of maximum crown breadth of modern Malay were made by the first author. All prehistoric South Asian comparative samples were measured by the first author, data for living East and South Asians were taken from published data. All statistical analyses were conducted using SAS, Inc. (9.1 for Windows). RESULTS: Crown dimensions, sex dimorphism and crown areas are presented and reveal consistencies in tooth size and level of sexual dimorphism with East and South Asian living samples. Sex dimorphism in Malay crown dimensions is low (1.1%) among Asians. Total crown area is 484.7 mm2, similar to living Japanese (486.3 mm2), but greater than Hindus (476.4 mm2) of India. Compared with prehistoric groups the Malay have reduced tooth size, especially when compared with Neolithic (MR 3, 535.3 mm2) and Chalcolithic (MR 2, 515.3 mm2) Mehrgarh, Pakistan. CONCLUSION: Sex dimorphism in Malay deciduous crown dimensions is lower than average among Asians and total tooth crown area is similar to living East and South Asians but is reduced when compared with prehistoric Asian samples.

Odontometria eletrônica em dentes decíduos: revisão de literatura e relato de caso / Eletronic working length determination in primary tooth: review of literature and case report

Objetivo: Realizar uma revisão dos principais artigos encontra-dos na literatura acerca do uso dos Localizadores Eletrônicos Foraminais (LEF) em dentes decíduos e representar através de um relato de caso clínico, a importância do uso destes dispositivos durante o tratamento endodôntico em dentes decíduos. Revisão da literatura: Foi realizada uma busca nas principais bases de dados, e selecionados 13 artigos consi-derados mais relevantes. Todos os estudos mostraram que a determinação da odontometria em dentes decíduos utilizando o LEF é bastante segura e com boa acurácia, podendo ser utilizado o localizador para esta finalidade. Relato do caso:No caso clínico apresentado, o uso do LEF foi fundamental para a obtenção de uma odontometria precisa, além da diminuição do tempo de cadeira e identificar reabsorções não detectáveis radiograficamente. O caso foi conduzido em duas sessões, onde na primeira foi realizada a cirurgia de acesso, odontometria eletrônica, preparo manual dos canais e utilização de medicação intracanal de hidróxido de cálcio. Na segunda sessão foi removida a medicação intracanal e os canais foram obturados utilizando pasta iodoformada. Discussão: O uso do LEF no tratamento endodôntico de dentes decíduos tem se mostrado uma ferramenta segura e eficiente, tendo melhor performance na determinação do comprimento de trabalho quando comparado a outros métodos. Conclusão: De acordo com os estudos apresen-tados na revisão de literatura e o caso clínico apresentado, pudemos constatar que o uso do LEF contribui positivamente ao tratamento, principalmente quanto ao ganho de tempo e determinação confiável e segura do comprimento de trabalho.

Aim: To review the main articles found in the literature on the use of Electronic Apex Locators (EAL) in deci-duous teeth, and to represent, through a clinical case report, the importance of using these devices during endodontic treatment in deciduous teeth. Review of literature: A search was performed in the main data-bases, and 13 articles considered most relevant were selected. All studies showed that the determination of odontometry in deciduous teeth using LEF is quite safe and with good accuracy, and the localizer can be used for this purpose. Case report: In the clinical case presented, the use of EAL was fundamental to obtain an accurate odontometry, besides the reduction of chair time and exposure to ionizing radiation. The case was conducted in two sessions, where in the first one the access surgery was performed, electronic odontometry, manual preparation of the canals and use of intracanal medication of calcium hydroxide. In the second session the intracanal medication was removed and the canals were filled using iodoform paste. Discussion: The use of LEF in the endodontic treatment of primary teeth has been shown to be a safe and efficient tool, with better permormance in determining the working length when compared to other methods. Conclusion: According to the studies presented in the literature review and the clinical case presented, we could verify that the use of LEF contributes positively to treatment, especially in terms of time gain and acurate determination of working length.

Biometry of width between labial transitional line angles in anterior teeth: an observational study.

PURPOSE: The maximum width between the mesial and distal labial transitional line angles, described as "esthetic width" herein, could significantly influence the visual perception of the teeth and smile. This study aimed to conduct biometric research on esthetic width and to explore whether regular distribution exists in the esthetic width of human teeth. MATERIALS AND METHODS: A total of 4,264 maxillary and mandibular anterior teeth were measured using the Geomagic studio software program. The proportions of maxillary to mandibular homonymous teeth and proportions between the adjacent teeth were calculated. Bilateral symmetry and the correlation between the esthetic and mesiodistal widths were both accounted for during the measurement procedures. RESULTS: The mean esthetic widths were 6.773 ± 0.518 mm and 4.329 ± 0.331 mm for maxillary and mandibular central incisors, respectively, 5.451 ± 0.487 mm and 5.008 ± 0.351 mm for maxillary and mandibular lateral incisors, respectively, and 3.340 ± 0.353 mm and 5.958 ± 0.415 mm for maxillary and mandibular canines, respectively. Except for the mandibular canines, no significant difference in esthetic width was found among homonymous teeth from the same jaw. A high linear correlation was found between the esthetic and mesiodistal widths of the same tooth, except for the maxillary canines. Esthetic width proportions among different tooth categories showed some regular patterns, which were similar to those of the mesiodistal width. CONCLUSION: Esthetic width is regularly distributed among the teeth in the Chinese population. This could provide an important reference for anterior dental restorations and dimension recovery in esthetic reconstruction of anterior teeth.

Influence of heat treatment of nickel-titanium instruments on the accuracy of an electronic apex locator integrated with endodontic motor.

Context: Manufacturers have produced a wide variety of nickel-titanium (NiTi) alloys, but the available literature is limited on the accuracy of some integrated electronic apex locators (EAL) used with different NiTi heat treatments in working length (WL) determination. Aim: This study aims to evaluate ex vivo , the influence of different heat treatments of NiTi instruments, and the diameter of the apical preparation on the accuracy of an EAL used during root canal preparation using an integrated EAL and motor unit. Materials and Methods: Nineteen extracted human mandibular incisors were included in the study. The WL control was determined by the visual method. Instruments of Mtwo, Reciproc, Reciproc Blue, WaveOne Gold, Twisted File Adaptive, and Hyflex CM systems, with diameters from 0.25 mm to 0.50 mm, were used to measure WL during root canal preparation. The electrical resistivity of instruments with a diameter of 0.25 mm from each system was evaluated using an Inductance, Capacitance, and Resistance (LCR) meter. Statistical Analysis Used: Data were statistically analyzed using Fisher's exact test and Kruskal-Wallis test. Results: The different heat treatments and different diameters did not influence the precision of the EAL (P > 0.05). Conclusion: The heat treatment and the diameter of the apical preparation did not influence the accuracy of WL determination by an EAL integrated with the endodontic motor.

Concordância entre medida de comprimento de trabalho por radiografia e localizador eletrônico foraminal na dentição decídua: revisão integrativa / Agreement between work length measurement by radiography and electronic foraminal locator in the primary dentition: an integrative review

Introdução: O estabelecimento do comprimento de trabalho (CT) é uma etapa fundamental para o sucesso do tratamento endodôntico, principalmente na dentição decídua. O exame radiográfico é um dos principais meios de definir o CT. A mensuração desse comprimento também pode ser obtida por meio de dispositivos eletrônicos. Objetivo: Revisar a literatura acerca da concordância entre a medida de CT por radiografia e localizadores eletrônicos foraminais (LEFs) na dentição decídua. Metodologia: A busca bibliográfica foi realizada nas bases de dados PubMed, Cochrane Library e BVS, seguindo uma estratégia de combinação de palavras-chave, filtrando apenas pesquisas clínicas. A seleção dos artigos foi realizada em duas etapas: através da leitura dos títulos e resumos e, em seguida, por meio da obtenção e leitura dos artigos completos selecionados. Resultados: sete artigos foram selecionados, publicados entre 2011 e 2020. Todos foram analisados quanto à qualidade metodológica e à caracterização como tamanho da amostra, objetivo, metodologia, resultados e conclusão. Todos possuíam os dados necessários para contemplar o objetivo desta pesquisa. O uso dos LEFs mostrou-se tão preciso quanto o método radiográfico (n=6), e, em um estudo, o método eletrônico foi superior ao radiográfico para determinação do CT. Conclusão: O método eletrônico possui eficácia na determinação do CT durante o tratamento endodôntico de dentes decíduos sendo comparável ao radiográfico.

Introduction: To establish the working length (CT) is a fundamental step toward the suc-cess of endodontic treatment. Also, the radiographic examination is one of the most important means of determining CT. This length can also be measured by electronic devic-es. Objective: To review the literature on the agreement between the CT measurement by radiography and electronic foraminal locators (LEF) in the primary dentition. Methodology: A bibliographic search was performed on PubMed, Cochrane Library, and BVS, using a keyword combination strategy and filtering only clinical research. The selection of the articles occurred in two stages: by reading the titles and abstracts, and by obtaining and reading the selected full articles. Results: Seven articles, published between 2011 and 2020, were selected and analyzed for methodological quality and characterized for sample size, objectives, methodology, results, and conclusion. They had the essential data to contemplate the purpose of this research. The use of LEF proved to be as accurate as of the radiographic method (n=6), and in one study, the electronic method was superior to the radiographic method for determining TC. Conclusion: The electronic method is effective in determining the CT during the endodontic treatment of primary teeth and is comparable to the radiographic one.

Root canal length changes during mechanical preparation due to different cervical enlargement patterns

Abstract This study aimed to evaluate the root canal real length (RL) changes due to the mechanical instrumentation use with different flaring magnitudes. After access cavity, 60 mesial root canals of mandibular molars were randomly separated in three groups: Hyflex EDM (HF; #25/.12, #10/.05 e #25/~), Reciproc Blue (RB; R25), and MTwo (M2; #10/.04, #15/.05, #20/.06 e #25/.06). The RL was defined as the apical limit, and 2.5% sodium hypochlorite irrigating solution was chosen. After the access cavity (RL 1), cervical flaring (RL 2), and complete chemical-mechanical preparation (RL 3), the RL was evaluated. The RL was evaluated by a blind examiner with the aid of a microscope (16x) placing the endodontic file stop at the coronary reference. When comparing length measurements, the RL was shorter before instrumentation than that after instrumentation. A reduction of 0.65 mm (HF), 0.61 mm (RB), and 0.48 mm (M2) was observed. However, among groups, no statistical differences were found (p > 0.05). Under the conditions tested, it can be inferred that all mechanical systems provoked RL variations, which emphasizes the need for constant verification of the odontometry, mainly before root canal obturation.

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

Uno de los métodos más universales empleados para predecir el ancho mesiodistal de caninos y premolares no erupcionados es el diseñado por el Dr. Edison Moyers, quien tomando como referencia la población anglosajona creó tablas de percentiles para estimar dichos valores en maxilar y mandíbula. Durante la última década varios investigadores han descubierto que, al aplicarlo en diversas poblaciones, existen diferencias significativas entre las predicciones y los valores reales. En Cuba, el método de Moyers es muy utilizado al 50% de probabilidades para la predicción en ambos sexos, pero existen pocos reportes de estudios que validen su confiablidad y los que existen utilizan muestras pequeñas de pacientes. Es por ello por lo que el objetivo de esta investigación es determinar la aplicabilidad del método de Moyers al 50% de probabilidades para la estimación del diámetro mesiodistal de caninos y premolares en pacientes de 12-18 años. Se desarrolló un estudio descriptivo y transversal desde julio de 2019 hasta febrero de 2020 con una población de 125 pacientes, 62 del sexo femenino y 63 del masculino, 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 de Moyers tiende a subestimar los valores para el sexo femenino entre los 0,4-0,5 mm, y para el sexo masculino entre los 0,6-0,7 mm, siendo esta diferencia significativa para los hombres. Se concluye que el método de Moyers no puede ser aplicado en la población estudiada para la predicción del ancho mesiodistal de caninos y premolares

One of the most universal methods used to predict the mesiodistal width of non-erupted canines and premolars is the one designed by Dr. Edison Moyers, an American orthodontist who, taking the Anglo-Saxon population as a reference, created percentile tables to estimate these values in the maxilla and mandible. During the last decade, several researchers have discovered that, when applied to various populations, there are significant differences between predictions and actual values. In Cuba, it is widely used at a 50% probability for prediction in both sexes, but there are few reports of studies that validate its reliability and those that do exist use small samples of patients. For this reason, the objective of this research is to determine the applicability of the Moyers method at 50% probabilities for estimating the mesiodistal diameter of canines and premolars in patients 12-18 years of age. A descriptive and cross-sectional study was developed from July 2019 to February 2020 with a population of 125 patients, 62 females and 63 males, between 12 and 18 years old from Cuba. Measurements were made of the mesiodistal widths of the lower incisors, all the canines and premolars. Frequency distributions were made to the variables studied and the results were presented in statistical tables. To verify the existence of significant differences, the statistical t-Student test was used. The main results obtained were that the Moyers method tends to underestimate the values for the female sex between 0.4-0.5 mm, and for the male sex between 0.6 and 0.7 mm, this difference being significant for men. It is concluded that the Moyers method cannot be applied in the population studied for the prediction of the mesiodistal width of canines and premolars

New Approach to Dental Morphometric Research Based on 3D Imaging Techniques.

Recent progress in imaging and image processing techniques has provided for improvements in odontological research in a variety of aspects. Thus, the presented method has been developed precisely in order to assess metrically 3D reconstructions of teeth. Rapidly and accurately obtained data of a wide range and appropriate density are sufficient enough for morphometric studies rather than tooth size assessments which are inherent to conventional techniques. The main contributions providing for holistic and objective morphometric analysis of teeth are the following: (1) interpretation of basic dental morphological features; (2) automated of orientational coordinate system setup based on tooth surface analysis; (3) new tooth morphometric parameters which could not be obtained through application of conventional odontometric techniques; (4) methodological novelty for automated odontomorphometric analysis pipeline. Application of tomographic imaging, which has been used for obtaining 3D models, expands the proposed method potential further through providing detailed and comprehensive reconstructions of teeth. The current study was conducted on unique material from the archaeological site of Sunghir related to the Upper Palaeolithic period. Metric assessments of external and internal morphological layers of teeth were performed in common orientation and sectioning. The proposed technique allowed more profound analysis of Sunghirian teeth which date back to the times of modern human morphology formation.

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.

Análise comparativa da precisão de medição dos localizadores apicais eletrônicos Romiapex a15® e Root zx mini®: um estudo in vitro / Comparative analysis of the measuring accuracy of the electronic apex locators Romiapex a15® and Root zx mini®: an in vitro study

Este estudo analisou a precisão de medição dos aparelhos ROMIAPEX A 15® e ROOT ZX MINI®, in vitro, comparativamente pelo método radiográfico e eletrônico no que diz respeito à precisão e confiabilidade na determinação do Comprimento Real de Trabalho (CRT) e Comprimento Real do Dente (CRD). Vinte dentes humanos (incisivos superiores e pré-molares superiores/inferiores) foram avalia das e seus CRD's e CRT's aferidos de forma direta por meio de lima tipo k nº 10 ou 15 (Dentsply Sirona, Ballaigues, Suíça), pelo método radiográfico e método eletrônico. Não foram verificadas diferenças significativas entre as medidas para CRD (p=0,003) e CRT (p=0,042) entre os métodos direto, radio gráfico e eletrônico. Ambos os métodos ficaram próximos da medida real, quando por vezes também definiram a mesma medida real. Os CRD's obtidos pelos métodos radiográfico e eletrônico foram sub metidos ao Teste t de Student (p<0,024) apontando relação estatística significativa para a verificação da odontometria, sugerindo que ambos os métodos são eficazes na determinação do comprimento real do dente quanto de trabalho. O método eletrônico apresentou eficácia satisfatória estatistica mente nos casos comparativamente aos outros métodos também avaliados. Os dados sugerem que os localizadores citados podem auxiliar as tomadas de decisões para determinação do CRD e CRT

This study analyzed the measurement accuracy of the ROMIAPEX A15® and ROOT ZX MINI® locators, in vitro, comparatively by the radiographic and electronic methods with regard to the precision and reliability in the determination of the Real Working Length (RWL) and Real Tooth Length (RTL). Twenty human teeth (upper incisors and upper/lower premolars) were evaluated it had the RTL and RWL measured through rasp k No 10/15 (Dentsply Sirona, Ballaigues, Switzerland) by radiographic and electronic methods. There were no significant differences between the measures for RTL (p = 0,003) and RWL (p = 0,042) for the methods. It means that both methods were very close to the real measure, when sometimes they also defined the same real measure. The RTL obtained by methods radiographic and electronic, were submitted to Student's t test (p <0,024), showed statistical significance in relation to the methods used for verification of odontometry, which means that both methods are effective to determine an actual length of the element and the length of actual work. The electronic method showed statistically satisfactory effectiveness in the cases compared to the other methods.The data suggest that these locators can assist decision making to determine RTL and RWL ... (AU)