Incisor Length Research Articles

Facial indicator in the determination of maxillary central incisor length in Nepalese population – A clinical study

Background: The maxillary anterior teeth are important in achieving pleasing facial and dental esthetics. Among those, the central incisor has a key role in determining the esthetic as they are the most dominant and visible teeth during smile. Determining the proper size of these teeth is important but difficult in the absence of pre extraction records in edentulous condition. Aims and Objectives: This study was conducted to find a suitable guide in determining the length of the central incisor by correlating it with some independent facial structure like nose length in a small population of Chitwan district. Materials and Methods: The distance from the bridge of the nose to the base was compared to the length of the maxillary central incisor in 321 patients of both sexes between the age groups of 20–35 years. The actual length of the maxillary incisor was measured and also calculated by regression analysis to determine some fixed ratio. The calculated value by this ratio was compared to the actual measured value to find if the difference was significant. Results: The difference between the calculated distances and the actual measured distance was found to be 0.340 in males and 0.266 in females, which was statistically significant (P<0.001). Conclusion: The distance from the bridge of the nose to base of the nose may be used as a reference to estimate the length of the central incisor in the Nepalese population, although sample included subjects from the central Chitwan District of Nepal.

Morphometric and volumetric analysis of the proximity between the incisive canal and maxillary central incisors during anterior retraction: a retrospective cone-beam computed tomography study.

To elucidate the relationships and factors affecting the proximity between the incisive canal (IC) and maxillary central incisors and to predict the probable outcomes after anterior tooth retraction using cone beam computed tomography (CBCT). Retrospective CBCT data taken before and after maxillary anterior retraction in 36 patients were used in this study. The incisive canal length (ICL), maxillary central incisor length (TL), angles between the palatal plane and axes of the maxillary alveolar border (θ1), IC (θ2), and maxillary central incisor (θ3), retraction distance (TDE), distance from the maxillary central incisors to the IC (D), cross-sectional area of the IC (CSA), and volume of the IC were evaluated. Comparison of the parameters between contact and noncontact groups were examined. Logistic regression was performed to analyze the probable outcome prediction. All parameters significantly decreased after anterior retraction, except for the ICL. Eighteen roots in 12 patients contacted the IC. The θ1, θ2, θ3, and D values at all levels were significantly lower, whereas the TDE, midlevel and oral opening CSA, and volume were significantly higher in the contact group compared with the noncontact group. The larger the pretreatment θ1 and θ3 were, the higher was the chance of incisors not contacting the IC. Maxillary central incisors not contacting the IC after anterior retraction was positively associated with larger degrees of pretreatment maxillary alveolar bone angle and maxillary central incisor angle.

A RADIOGRAPHIC ANALYSIS OF EXTERNAL APICAL ROOT RESORPTION (EARR) OF MAXILLARY INCISORS AFTER 6 MONTHS OF INITIATION OF FIXED ORTHODONTIC APPLIANCE THERAPY

Consequences of External apical root resorption (EARR) range from slight tooth mobility due to mild amounts of root resorption to complete loss of teeth due to excessive root resorption. The purpose of this study was to measure the amount of EARR that might occur on the 4 maxillary incisor teeth while using the MBT system and to evaluate its clinical signicance during a 6-month period of active treatment. In addition, the contribution of gender, and how extraction and non-extraction of premolars is related to maxillary incisor EARR was examined. A sample of 40 patients between 12 -20 years of both genders reporting to the Department of Orthodontics & Dentofacial Orthopaedics of KD Dental College was selected for this study. The amount of EARR for the 160 teeth was examined. There was no statistically signicance difference (p>0.05) found between change in root length of Maxillary right Central incisor, Maxillary right lateral incisor, Maxillary left central incisor and Maxillary left lateral incisor. There was no statistically signicant difference was found among male and female with EARR and there was no statistical difference (p>0.05) found in external apical root resorption among participants with premolar extraction and without premolar extraction. This study concludes that all the maxillary incisors in this investigation did not show any kind signicant EARR after the follow-up period of 6months of active orthodontic treatment with MBT treatment techniques, no signicant changes in EARR was observed when comparison was made for gender and also for treatment where premolar extraction was done.

Augmented corticotomy-assisted presurgical orthodontic treatment to prevent alveolar bone loss in patients with skeletal Class III malocclusion

The objective of this study was to explore the effect of augmented corticotomy (AC) on anterior alveolar bone morphology in presurgical orthodontic treatment for skeletal Class III malocclusion. Thirty-six surgical patients with skeletal Class III malocclusion with high-angle were included: 18 (AC group) accepted AC surgery during presurgical orthodontic treatment, and 18 (control group) accepted traditional presurgical orthodontic treatment. Cone-beam computed tomography scans were obtained before treatment (T0) and after presurgical orthodontic treatment (T1). The alveolar bone morphology, root length, dehiscence, and movement of mandibular central incisors were measured by cone-beam computed tomography using Dolphin software. Statistical analyses were performed with independent-sample t tests, paired t tests, and multiple linear regression. After presurgical orthodontic treatment, the whole alveolar bone thickness at each level, alveolar bone area, and alveolar bone height decreased significantly in the control group but increased or remained unchanged in the AC group. In the AC group, the lower the labial alveolar bone height at T0 was, the greater the increase after T1; the change in alveolar bone thickness was related to ΔL1-MP and sex. At T0, the incidences of dehiscence were similar in the 2 groups, ranging from 11.11% to 16.67%. At T1, the labial and lingual incidences of dehiscence in the AC group were 0% and 27.78%, compared with 55.56% and 66.67% in the control group. During presurgical orthodontic treatment, AC is effective in preventing alveolar bone resorption and dehiscence without additional root resorption. AC can be recommended for high-angle skeletal Class III patients with thin alveolar bone around anterior teeth during presurgical orthodontic treatment.

Estimation of Dental Age Using the Kvaal Method with Digital Panoramic Radiographs in Peruvian Adults

To determine the accuracy of the Kvaal method in the estimation of dental age through the analysis of digital panoramic radiographs of patients between 20 and 47 years of age who attended the stomatological clinic of the Universidad Científica del Sur, (2018 to 2019), Lima-Perú. 289 digital panoramic radiographs belonging to individuals of both sexes, aged 20 to 47 years were analyzed. Length and width measurements were obtained in the dental and pulp chamber in the upper central incisors. These data were subsequently evaluated by calculating the proportions between the pulp and root length of the upper central incisor by applying the formula of the method of Kvaal et al. to obtain the accuracy of the method in estimating dental age. Applying the formula of Kvaal et al. indicates that the relationship between the width of the pulp and the length of the root has a higher level of significance in relation to others proportions: M mean value of all ratios except T (-0.659) and W-L difference between W and L (-0.643). The coefficient of determination (r²) and standard error of estimation (SEE) using the original Kvaal formula is r²: 0.70, SEE: 4.90 years, then a modified Kvaal formula was proposed for the Peruvian population. The Method of Kvaal et al. has an accuracy of 1.24 in estimating the dental age of individuals, using the upper central incisor in digital panoramic radiographs.

Reliability and accuracy of dental MRI for measuring root canal length of incisors and canines: a clinical pilot study

To evaluate whether high-resolution, non-contrast-enhanced dental MRI (dMRI) can reliably and accurately measure the canal length of incisors and canines compared with cone-beam computed tomography (CBCT). Three-Tesla dMRI was performed in 31 participants (mean age: 50.1 ± 14.2 years) with CBCT data. In total, 67 teeth were included (28 from the upper jaw and 39 from the lower jaw; 25 central incisors, 22 lateral incisors, and 20 canines). CBCT and dMRI datasets were reconstructed to visualize the root canal pathway in a single slice in the vestibulo-oral (V-O) and mesio-distal (M-D) direction. Root canal length was measured twice by two radiologists using dMRI and CBCT. Data were statistically analyzed by calculating intraclass correlation coefficients (ICCs) and performing Bland–Altman analysis. The reliability of dMRI measurements was excellent and comparable to that of CBCT measurements (intra-rater I/intra-rater II/inter-rater was 0.990/0.965/0.951 for dMRI vs. 0.990/0.994/0.992 for CBCT in the M-D direction and 0.991/0.956/0.967 for dMRI vs. 0.998/0.994/0.996 for CBCT in the V-O direction). According to Bland–Altman analysis, the mean (95% confidence interval) underestimation of root canal lengths was 0.67 mm (− 1.22 to 2.57) for dMRI and 0.87 mm (− 0.29 to 2.04) for CBCT in the M-D direction/V-O direction. In 92.5% of cases, dMRI measurements of canal length had an accuracy within 0–2 mm. Visualization and measurement of canal length in vivo using dMRI is feasible. The reliability of dMRI measurements was high and comparable to that of CBCT measurements. However, the spatial and temporal resolution of dMRI is lower than that of CBCT, which means dMRI measurements are less accurate than CBCT measurements. This means dMRI is currently unsuitable for measuring canal length in clinical practice.

Cone-beam CT analysis of external root resorption of maxillary incisors before and after traction of impacted canines

Objective: To analyze the external root resorption of incisors caused by maxillary canine impaction, and to explore the changes of incisor external root resorption after orthodontic treatment. Methods: Twenty-four patients with impacted maxillary canines leading to external root resorption of incisors treated in Department of Orthodontics, Affiliated Hospital of Stomatology, Nanjing Medical University from July 2011 to January 2019 were selected. The age ranged from 10 to 14 years [(12.3±1.6) years], including 11 males and 14 females. The maxillary incisors with external root resorption before treatment were included in the resorption group (21 central incisors and 22 lateral incisors), and the maxillary incisors without external root resorption were used as the control group (26 central incisors and 21 lateral incisors). Cone-beam CT was taken before treatment, immediately after treatment and one year after treatment. At the one year follow-up 15 patients were collected (10 central incisors and 12 lateral incisors in the resorption group, while 16 central incisors and 12 lateral incisors in the control group). The root length and tooth volume of maxillary incisors were measured and analyzed before canine traction, after canine traction finished and at the one year follow-up. Results: After the treatment of maxillary impacted canines, the root length and volume of the central and lateral incisors in both resorption group and control group were significantly less than that before treatment (P<0.05). At the one year follow-up, the root length and volume of the incisors (central incisors in the resorption group and the central and lateral incisors in control group) were significantly less than those immediately after impacted canine traction (P<0.05). During the canine traction, the difference of the volume change in lateral incisors between the resorption group [(17±6) mm3] and the control group [(12±5) mm3] was statistically significant (t=2.51, P<0.05). During the one year follow-up period, the difference between the changes of the root length in maxillary central incisors in the resorption group [(0.5±0.4) mm] and in the control group [(0.2±0.1) mm] was statistically significant (t=2.35, P<0.05). Conclusions: For maxillary incisors with external root resorption caused by impacted maxillary canines, the external root resorption could not stop immediately after the treatment of impacted canines. The root resorption in maxillary lateral incisors mainly occured during the traction process, while the root resorption in maxillary central incisors existed during the orthodontic treatment and in the follow-up period.

Symmetrical comparison of crown size, morphology and gingival shape in maxillary incisors

Background: Maxillary anterior tooth proportion has special value in dental aesthetics. Restorative dentistry often involves correcting tooth size discrepancies. Therefore, dental biometrics should play an important role in the planning of an aesthetic restoration. Objectives: To assess and compare clinical crown dimensions and classify crown shape and gingival shape of the maxillary incisors in order to collect anatomical data on the anterior teeth of young population visiting the tertiary centre. Methods: This descriptive cross-sectional study conducted in department of Prosthodontics in November 2021 after getting ethical approval among dental students and patients attending the hospital, with permanent healthy dentitions. Impression of maxillary and mandibular arches were made with alginate and poured in dental stone. Measurement of maxillary central incisors was done for length and thickness with the digital vernier calliper. Convenience sampling was done. Data were recorded and analysis done with SPSS v.20. Results: The mean value of crown length, crown thickness, mesiodistal width of left central incisor was greater compared to the right side (Left vs Right: 9.01 ± 1.14 mm vs 9 ± 1.14 mm , 7.04 ± 0.67 mm vs 6.96 ± 0.61 mm, 8.25 ± 0.59 mm vs 8.20 ± 0.51 mm). Conclusion: Crown length and crown width of maxillary left central incisor were greater compared to maxillary right central incisor. Shape of maxillary incisors determines the shape of the gingiva. The average values of length and widths of the central incisors derived from this study can be a valuable template for prosthodontic and aesthetic planning.

Comparison Between Human Maxillary Anterior Teeth and Commercial Acrylic Teeth: A Sex-Stratified Analysis

Objective: The aim of this study was 1.To compare the total width of human anterior teeth from different races (White, black, and Asian) to the total width of commercially available anterior teeth molds and, 2. To compare the width and length of human central incisors (#9) from different races (White, black, and Asian) with those of commercially available central incisors (#9). Materials and Methods: The study consisted of 360 participants, with 60 females and 60 males in each of 3 racial groups: White, Black, and Asian. Metric measurements of natural teeth were obtained from dental casts, and those of acrylic teeth were obtained from company catalogs. Statistical Analysis: Data normality was determined by Kolmogorov-Smirnov and Shapiro-Wilk tests. The Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner post hoc tests were used to compare measurements across the racial groups and commercial acrylic teeth. P value of ≤ 0.05 was set as statistically significant. Results: The results showed significant intra- and intergroup differences between males and females and across the 3 racial groups, especially among the Black group. Significant differences were also detected between artificial and natural teeth dimensions. Conclusion: Although similarities exist, generally, the dimensions of commercially available artificial teeth are different than that of natural teeth in the studied populations. Overall, in both males and females, the median length of natural tooth #9 is always smaller when compared to commercially available teeth. In contrast, in both males and females, the median width of natural tooth #9 is always larger when compared to commercially available teeth, except for female Asian population. Overall, significant racial differences exist in the length, width, and total width of natural teeth compared to commercially available teeth in the Black population. However, both the white and asian population showed less significant differences when comparing the length, width, and total width of natural teeth to commercially available teeth.

Dimensional and morphologic characteristics of unilateral impacted maxillary central incisors

This cross-sectional study aimed to investigate the crown and root characteristics of impacted central incisors compared with spontaneously erupted contralateral incisors and the influence of etiologic and local factors on their dimensions. Forty-five patients (22 boys, 23 girls) who underwent orthodontic treatment for unilateral impaction of maxillary central incisors were referred for cone-beam imaging. Dimensions of the impacted and contralateral incisors were assessed using Dolphin 3D software (Dolphin Imaging & Management Solutions, Chatsworth, Calif). Paired t test and linear regression were used to compare the characteristics of the impacted and contralateral teeth. Contralateral and impacted central incisors showed statistically significant differences for root length (95% confidence interval [CI], 2.32-3.46; P<0.001), mesiodistal crown-root angulation (95% CI, 4.09-15.95; P= 0.001), and labiolingual crown-root angulation (95% CI, -18.69 to -4.70; P= 0.002). Etiologic factors did not alter the dimensions of incisors (95% CI, -1.17 to 0.76; P= 0.672). According to the multiple linear regression the independent variables associated with root length of contralateral and impacted incisors were sex (β= -0.904; 95% CI, -1.62 to - 0.19; P= 0.014) and the presence of impaction (β= -2.87; 95% CI, -3.67 to -2.07; P<0.001). Regardless of their etiology, the impacted incisors showed roots that were 2.89 mm shorter than the contralateral incisors and had greater angulation in the mesiodistal and labiolingual directions. Girls showed a reduction of 0.904 mm (7.6%) on the lengths of roots of both impacted and contralateral central incisors. The presence of impaction led to a reduction of 25% in incisor root lengths. Approximately 30% of the impacted teeth showed crown-root angulations>20° resulting in an increased distal and labial angulation of the root apical portion.

The Morphology of Impacted Maxillary Central Incisors: A Systematic Review.

Background and Objectives: The knowledge of the morphology of impacted maxillary central incisors may lead to more effective treatment. Therefore, this systematic review aimed to evaluate the morphology of impacted maxillary central incisors and compare them with contralateral teeth. Material and methods: This systematic review adhered to the PRISMA statement. The literature search was carried out using PubMed (Medline database), Cochrane Library, ProQuest, Web of Science and Science Direct electronic databases with no publication date restrictions up to July 2021. Data assessing the morphology of unilaterally impacted maxillary central incisors (ICI) evaluated with CBCT were extracted, and the quality of the studies was evaluated. Crown length, root length, and root dilaceration of impacted maxillary central incisors were compared with contralateral unimpacted teeth. Results: The initial database search identified a total number of 287 studies. After applying the selection criteria, 21 articles were selected for a full-text analysis, and four retrospective studies involving 205 patients were included in the systematic review. According to the Newcastle-Ottawa Scale (NOS), two of included articles were graded as “Good” and the remaining two as “Fair” quality. The results showed no difference between impacted teeth and their contralateral crowns, or a minor decrease in ICI crown length (from 0.15 to 0.56 mm). The root lengths of impacted maxillary central incisors were considerably shorter than contralateral incisors (from 2.13 to 3.22 mm) and, as dental age increased, root growth decreased and the incidence of root dilaceration was more frequent. Conclusions: The root lengths of impacted maxillary central incisors were considerably shorter compared to the contralateral incisors. Root dilacerations frequency and severity increased as dental age increased.

Skeletal and Dental Morphological Characteristics of the Maxillary in Patients with Impacted Canines Using Cone Beam Computed Tomography: A Retrospective Clinical Study.

The aim of this study is to analyze the skeletal and dentoalveolar morphological characteristics of the maxillary in subjects with a unilateral palatally impacted canine using Cone Beam Computed Tomography (CBCT). A retrospective clinical study was conducted of 100 adult patients divided into two groups: one consisting of patients with a unilaterally palatally impacted maxillary canine (GI), with the subgroups in the right and left hemiarches (GI-R and GI-L), and the second, without impacted canine, as the control group (CG). The CBCT measured skeletal variables (maxillary basal width and alveolar crest height) and dentoalveolar variables (inclination of the upper incisor, tooth lengths of incisors and canines, arch length, tooth size and bone dental discrepancy). In skeletal variables, statistically significant differences were found in alveolar crest height (ACH) in all groups and subgroups (p < 0.01). In the dentoalveolar variables, there were differences in the angle of the upper incisor (II) and lateral incisor length (LLIL) between the GI and GC and the angle of the upper incisor (II′), arch length (AL′) and arch length-tooth size discrepancy (ATD′) among the GI subgroups (p < 0.01). There are skeletal and dentoalveolar differences in patients with unilateral palatally impacted maxillary canines, with lower angular and linear measurements compared with patients without impaction.

Biometric Assessment of Maxillary Anterior Tooth Dimensions in a Hong Kong SAR Population

Objectives: To study the biometric dimensions of upper front teeth in a Hong Kong SAR population including gender differences and compare this with the often recommended use of the Golden Proportion when selecting tooth proportions. Methods: A sample of dental casts was obtained from 100 patients: 50 females and 50 males with an age range from 18 to 35 years. The sample was selected based on the criteria of intact maxillary anterior dental arches, free from imbrications and crowding, no restorations or replaced teeth in the upper front teeth. The width and length of the 600 upper anterior teeth included in the casts were measured, together with the combined upper anterior tooth width for each cast. Analysis of width/height ratio, sexual dimorphism, and golden proportions was statistically analyzed. The data was analysed by SPSS using one-sample t-test, two-sample t-test, and paired t-test. Results: Most measurements had a normal distribution. Paired sample t-test revealed that the average length of male maxillary incisors is significantly higher than female maxillary incisors, while there is no obvious difference in maxillary incisor width. The mean width/length ratio of maxillary incisors ranges from 0.78 to 0.87. The mean values of maxillary apparent tooth width prove that the golden proportion (GP) ratio 1.618 was absent in the current sample. The current study data shows that the mean values of tooth width and length differed from some other populations. Conclusions: Based on the findings of this research, there is no statistically significant difference in the maxillary anterior tooth dimensions for the right and left sides of the arch. Length and width dimensions of the central incisor (CI) were greater than those of lateral incisor (LI) and Canine (C) for both genders, suggesting CI to be the dominant anterior tooth. Some gender differences in tooth dimensions, with males tend to have longer tooth dimensions than females, the average width/length ratio of the female is higher than male, which confirms that the male tends to have longer teeth. The result shows the absence of golden proportion (GP) ratios suggesting that the Golden Proportion guideline was not applicable for the Hong Kong SAR population for either gender.

Stature estimation using minimum Armamentarium in Himachali population: A Cross sectional study on Odontometry and skull Anthropometry

Background: When the body has been mutilated or fragmented in case of mass destruction and disasters, it is common to have head or extremities to get separated from the trunk. In relation with forensic odontology, an estimate must have been made to correlate osteometry along with odontometry in determining gender and race. Aim: To investigate the relationship between stature of a person with the diameter of the skull, the circumference of the skull, combined mesio-distal width of the maxillary anterior teeth, the length of the maxillary central incisor as well as with the length of foot using minimum and easily available armamentarium . Materials and Methods: The study was conducted in 100 subjects (50 males and 50 females) who visited the department of Oral Medicine and Radiology of from June, 2019 to August, 2019 for diagnostic and treatment purposes. Hundred model casts of patients were made to measure the width of the maxillary anterior teeth and the length of the maxillary central incisor. The circumference of the head, the diameter of head (distance from glabella to inion) the length of the foot and height were measured with the help of non- stretchable measuring tape. The selected parameters were measured and then correlated to estimate the stature from anthropometric and odontometric data of the skull by using linear regression analysis. Results: The selected parameters on linear regression analysis were found to be statistically significant for estimation of stature. Highly significant correlations were found between the stature, the head diameter and the length of foot in males. Conclusion: The present study showed that linear regression equations from the skull and odontometrics parameters can be used to estimate the stature. However longitudinal studies with larger sample size and appropriate apparatus should be done to substantiate the results in a specific population.

Association Between Impacted Maxillary Canines and Adjacent Lateral Incisors: A Retrospective Study With Cone Beam Computed Tomography.

The goal of this study was to evaluate the association between the morphologic characteristics of maxillary lateral incisors and maxillary canine impaction by using cone beam computed tomography (CBCT) images. CBCT images of 52 patients (19 male and 33 female) with unilateral impacted maxillary canines were selected. The volume, root, and total lengths of the lateral incisor, mesiodistal and buccolingual widths of the lateral incisor crowns, angles between the central axis of the lateral incisor and the midline, occlusal plane, and the central axis of canines in both the impacted and non-impacted side were measured and compared. Statistically significant differences were obtained when comparing the volume of the lateral incisor, the mesiodistal and buccolingual widths of the lateral incisor crown, the root and total lengths of the lateral incisors, and angles between the central axis of the lateral incisor and the midline and the central axis of the adjacent canine (P < .05). There were no significant differences in lateral incisor axis and the maxillary occlusal plane angulation. The association between the morphologic and angular features of the maxillary lateral incisors and maxillary canine impaction was confirmed. The volume of the lateral incisor, mesiodistal and buccolingual width of the lateral incisor crown, root and the total length of the lateral incisor, and the lateral incisor angulation to the midline and the axis of adjacent canine were found to be strong predictors of maxillary canine impaction.

Age estimation of Arabian mares by incisors morphometry and dentition changes.

Accurate estimation of a horse's age based on the condition of the tooth status is necessary as a scientific and artistic technique, which has not been performed so far in pure Arabian horses of Khuzestan (southern west of Iran). This study aimed to investigate the age-dependent changes in the morphology and morphometry of the incisors in Arabian mares of Khuzestan to estimate age and to compare the estimated dental age and actual age. In this study, 78 Arabian mares of Khuzestan were examined in several equestrian clubs. Then, images were taken with a digital camera from the vestibular and occlusal surfaces of the lower incisors. Parameters of deciduous and permanent teeth eruption and their number, occlusal surface changes in the lower incisors including appearance and disappearance of the cup, enamel spot, dental star and appearance, and changes of Galvayne's groove in the upper corner incisor were investigated. Comparison of the clinical crown length of incisors in each group showed that first, second and third incisors (I1, I2, and I3) had the maximum to minimum crown length, respectively. The correlation between actual age and clinical crown length was strong in I1 (r = 0.73, p ≤ 0.001), I2 (r = 0.8, p ≤ 0.001), and I3 (r = 0.81, p ≤ 0.001) in the Arabian mares of Khuzestan. The correlation of estimated dental age with actual age in the Arabian mares of Khuzestan was very strong (r = 0.992, p ≤ 0.001). Therefore, the dental age estimation in the Arabian mares of Khuzestan appears to be very close to the actual age of the animal.

Role of Facial Index and Odontometric Parameters in the Establishment of Stature and Gender of Individuals.

Background:Dental anthropology is an important aspect of bioarchaeology and forensic anthropology. In forensic anthropological studies, identifying an unknown individual from a mangled and decomposing body is a challenging task. Cranial remains are the only critical clues available for personal identification. Age, sex, and stature are significant parameters in establishing the identity of an unrecognized individual. Stature is the natural height of the individual in an upright position. Stature can be estimated from various parts of the body such as long bones, short bones, and skull. Few studies conducted in specific population have established a correlation for predicting stature from cephalometric and odontometric parameters. Thus, the present study was conducted to determine stature and gender based on cephalometric and odontometric parameters in the population of Tamil Nadu.Aims:The aim of this study was to investigate the possibility of predicting the stature and gender of an individual based on odontometric measurements, facial height, and bizygomatic width.Materials and methods:A total of seventy individuals in the age group of 18–24 years were selected for the study. The facial height, bizygomatic width and length ,mesiodistal and labiolingual diameter of clinical crown of maxillary central,lateral and canine teeth of both the right and left quadrants were measured. The values were analyzed statistically. Through this analysis, regression equations for estimation of stature from odontometric and facial index were derived.Results:Pearson correlation test was carried out to establish a correlation between the stature and the measured parameters. Regression analysis was carried out to establish stature from the odontometric and facial index of the individual. The regression equations were used to get estimated stature in the same sample of volunteers from which regression equations were obtained. Tabulated results showed a probable correlation between various parameters.Conclusion:In our study, a positive correlation between cephalometric measurements, gender, crown length of permanent left central incisor, and combined mesiodistal diameter of permanent maxillary anteriors with stature was found. This can be used as a supplementary method for estimating the stature of unknown human bodies.

Central incisors shape and proportions prevalence in Argentinian university students: by visual assessment and a new standardized method.

The aim of this study was to analyze the dimensions of the clinical crown of upper central incisors and the prevalence of tooth shapes by two different protocols. Assessment was performed on each of the 111 dental stone type V maxillae models of students of dentistry from Buenos Aires University [93 females and 18 males, mean age 23.70 (± 2.26) years] The mesial and distal-vestibular angles were defined on each right upper incisor, and the following segments were defined: AB (zenith - incisal edge), CD, EF, GH (apical, middle, and incisal thirds - vestibule - mesial and vestibule-distal angles) and their lengths were determined with a precision caliper. Then, the CD/AB, EF/AB and mean CD-EF/AB ratios were calculated. Shapes were assessed by four independent observers, three of whom evaluated digital images of the models, while the fourth had no access to the images, and determined the shapes using an algorithm developed from the dimensions of the studied segments. Rates and confidence intervals were determined, and Fleiss' Kappa was calculated to assess the agreement among the evaluators who worked with the images and among all of them. Average incisor length was 10 mm, and widths at CD and EF were 7.35 mm (0.65) and 8.27 mm (0.58), respectively. Regarding shapes, 51.58% (47.90-55.20) of the incisors were identified as square, 18.02% (14.50-21.90) as ovoid and 30.41% (30.00-30.90) as triangular. Fleiss' Kappa agreement was 0.71 (0.62-0.80). The application of the proposed algorithm provided a considerable level of agreement among the observers. Regarding tooth size, both the average segment length and the proportions were similar to those reported by various authors.

Accuracy of anterior denture tooth arrangements of CAD-CAM complete removable dental prostheses made with a tooth mold template

Statement of problemResearch evaluating the accuracy of anterior tooth mold templates to computer-aided design and computer-aided manufacture (CAD-CAM) fabricated complete removable dental prostheses (CRDPs) is limited. PurposeThe purpose of this in vitro study was to investigate the accuracy of the anterior denture tooth arrangement on CAD-CAM complete removable dental prostheses made with the anterior tooth mold template. Material and methodsA maxillary and mandibular edentulous model was mounted on a semiadjustable articulator to simulate a patient’s maxillary arch. Definitive impressions and jaw relation records were made as per the manufacturer’s protocol. A maxillary and mandibular anatomic measuring device was completely seated onto the edentulous models, centered on the edentulous model midline, and horizontally positioned parallel to the mandibular ridge. A medium-size anterior tooth mold template sticker was attached on the anatomic measuring device to identify the maxillary dental midline and incisal edge position and was sent to the manufacturer as the proposed tooth arrangement reference for the definitive complete removable dental prostheses. A total of 10 milled complete removable dental prostheses were generated for 2 groups by using 2 different tooth arrangement techniques. One group (n=5) used the monobloc milling technique without bonding of denture teeth, while the other group (n=5) used the bonding system for denture teeth on the milled denture base. For comparison, a camera mounted on a tripod was used for photographic documentation. Reference markers placed on the edentulous model were used to orient and measure the difference of 4 aspects of the anterior tooth arrangement: average incisal edge position, intercanine distance, midline, and clinical crown length of the left central incisor. The difference values between the tooth mold template and definitive complete removable dental prostheses were statistically analyzed by multivariate ANOVA (α=.05) and 1-sample t tests (adjusted α=.0125). ResultsOverall, statistically significant differences were found between the tooth mold template (control) and definitive complete removable dental prostheses at all measuring aspects except for the midline of the midline of the milled arrangement technique (P<.0125). In terms of the midline value, the value of the milled group did not show a significant difference compared with tooth mold template (-0.19 mm). However, the value of the bonded group indicated a significant difference of midline (0.44 mm toward to the left of the tooth mold template midline). When the complete removable dental prosthesis milled denture tooth and complete removable dental prosthesis bonded denture tooth techniques were compared, there was no difference in the tested variables between the milled and the bonded groups (P>.0125). ConclusionsThe tooth mold template did not represent an accurate position for definitive complete removable dental prostheses for either the milled or bonded techniques. The largest differences were found at the average incisal edge of the anterior teeth and the intercanine distance for both groups. However, there was overall no clinical difference between the 2 groups (milled and bonded) of CAD-CAM complete removable dental prostheses.

Lif Deficiency Leads to Iron Transportation Dysfunction in Ameloblasts

Leukemia inhibitory factor (LIF), a member of the interleukin 6 family of cytokines, is involved in skeletal metabolism, blastocyst implantation, and stem cell pluripotency maintenance. However, the role of LIF in tooth development needs to be elucidated. The aim of the present study was to investigate the effect of Lif deficiency on tooth development and to elucidate the functions of Lif during tooth development and the underlying mechanisms. First, it was found that the incisors of Lif-knockout mice had a much whiter color than those of wild-type mice. Although there were no structural abnormalities or defective mineralization according to scanning electronic microscopy and computed tomography analysis, 3-dimensional images showed that the length of incisors was shorter in Lif−/− mice. Microhardness and acid resistance assays showed that the hardness and acid resistance of the enamel surface of Lif−/− mice were decreased compared to those of wild-type mice. In Lif−/− mice, whose general iron status was comparable to that of the control mice, the iron content of the incisors was significantly reduced, as confirmed by energy-dispersive X-ray spectroscopy (EDS) and Prussian blue staining. Histological staining showed that the cell length of maturation-stage ameloblasts was shorter in Lif−/− mice. Likewise, decreased expression of Tfrc and Slc40a1, both of which are crucial proteins for iron transportation, was observed in Lif−/− mice and Lif-knockdown ameloblast lineage cell lines, according to quantitative reverse transcription polymerase chain reaction, immunohistochemistry, and Western blot. Moreover, the upregulation of Tfrc and Slc40a1 induced by Lif stimulation was blocked by Stattic, a signal transducer and activator of transcription 3 (Stat3) signaling inhibitor. These results suggest that Lif deficiency inhibits iron transportation in the maturation-stage ameloblasts, and Lif modulates expression of Tfrc and Slc40a1 through the Stat3 signaling pathway during enamel development.