Evaluation of the Golden Proportion, Golden Percentage, and Recurring Esthetic Dental Proportion in Kenyans of African Descent.

OBJECTIVES: To evaluate the validity of the Golden Proportion, Golden Percentage, and Recurring Esthetic Dental (RED) Proportion among Kenyans of African descent with naturally well-aligned teeth. MATERIALS AND METHODS: Standardized frontal photographic images of the smiles of 175 participants aged 18-35 years were obtained, and Adobe Photoshop was used to analyze and measure the frontal widths of the maxillary central and lateral incisors and canines in triplicate. The average teeth widths were calculated to determine the existence of the Golden Proportion, Golden Percentage, and RED Proportion, and their validity using independent sample t-tests to compare the differences in the mean teeth widths at α < 0.05. RESULTS: The number of male and female participants was 107 (61.1%) and 68 (38.9%), respectively. The Golden Proportion between the maxillary central and lateral incisors was found in 4.0% on the right and 2.8% on the left of all the participants, but between the maxillary lateral incisors and canines was found in only 0.6% on the right of male participants (p < 0.0001). The RED Proportion between the maxillary lateral and central incisors was in the range of 67%-70%, and between the canines and lateral incisors was 82%-84% (p < 0.0001). The proportion of RED was not constant, and gradually increased distally. The Golden Percentage of 15% was observed in the lateral incisors bilaterally; however, in the central incisors and the canines, the Golden Percentage was 22% and 12%, respectively. CONCLUSION: The Golden and RED Proportions were invalid determinants of anterior teeth proportions. The Golden Percentage existed only in the lateral incisors. The Golden Proportion, RED Proportion, and Golden Percentage theories may not be applicable to all populations when designing smiles. Racial and ethnic backgrounds are important considerations to establish objective quantifiable values of anterior tooth proportions that are beneficial for esthetic restorations.

The usefulness of ultrasonography as a dynamic measurement system for visualizing root canal working length: an in vivo study.

OBJECTIVE: Although apex locators are generally effective tools for determining root canal working length, they may produce inaccurate results in some cases. The present study aimed to evaluate the efficacy of ultrasonography as an alternative method for measuring root canal length. MATERIALS AND METHODS: Forty-seven anterior teeth with apical lesions were selected for the study. Initially, an electronic apex locator was used to measure the working length. Subsequently, ultrasonography was employed to visualize the root apex and determine the working length. During ultrasound imaging, a K-file No. 15 was inserted into the root canal until its tip was visible on the ultrasound monitor. Measurements obtained from both methods were compared using an independent sample t-test. Correlations were assessed with the Pearson correlation coefficient, and agreement was determined using the Bland‒Altman plot. RESULTS: The mean working canal length was 19.9 mm for the apex locator and 20.6 mm for the ultrasonography-guided method. No significant differences were observed between the data obtained using the apex locator method and the data obtained using the ultrasonography guidance method. Furthermore, a high level of agreement was identified between the two techniques. CONCLUSION: Ultrasonography can be used to visualize the apex effectively and determine canal length, especially when canal length determination is uncertain for various reasons.

Are deciduous upper molars and lower canines useful for sex estimation?

OBJECTIVE: This paper investigates whether deciduous upper molars and lower canines have sexual dimorphic features, exploring these teeth' dimensions and the presence of Zuckerkandl's tubercle and Carabelli's cusp on the first and second upper molars. DESIGN: We analyzed 64 pairs of dental plaster casts from 34 females and 30 males aged between 3 and 12 years. We measured the first and second deciduous upper molars and the lower deciduous canines (maximum mesiodistal and buccolingual length), and we registered the presence of the Zuckerkandl's tubercle and the Carabelli's cusp on the first and second upper molars, respectively. RESULTS: Regarding the differentiation between sexes using Carabelli's cusp and Zuckerkandl's tubercle, the classification was not independent of Carabelli's cusp presence only for tooth 65 (p = 0.035). In all other teeth, whether for Carabelli's cusp or Zuckerkandl's tubercle, their presence was similar for both sexes. There were statistically significant differences between sexes (p < 0.05) for the buccolingual measurements of both upper second molars, the first right upper molar, and the right canine. The developed model allowed for a 64.1% accuracy in sex estimation. CONCLUSIONS: The study suggests that while Carabelli's cusp and Zuckerkandl's tubercle in upper deciduous molars don't consistently differ between sexes, tooth size, particularly the buccolingual measurements of certain teeth, including upper deciduous molars and lower canines, may provide a more reliable criterion for sex estimation. The developed model depicted moderate accuracy, underscoring the need for a multifactorial approach when estimating sex from skeletal remains. It suggests that while dental features can contribute to sex estimation, they should be used in conjunction with other skeletal or molecular markers to improve accuracy.

Canine sexual dimorphism in crown and root dimensions: a cone-beam computed tomographic study.

The primary step in forensic odontological analysis is sex determination. The present study is one of the few studies that evaluated the accuracy of the combination of canine tooth root length and crown measurements for sex determination. The study sample comprised 196 cone-be am computed tomographic scans of individuals aged 20-80 years distributed in five age categories: 20-29, 30-39, 40-49, 50-59, and 60+ years old. Different parameters, such as width, length, and ratio measurements for the crown and root of each maxillary and mandibular canine tooth, were examined and recorded. The findings indicated that maxillary canines had greater sex dimorphism ability (87.3%) than mandibular canines (80.6%). Total tooth length and root length of maxillary canine were the most pronounced variables in the differentiation of sex groups. When the combination of the mandibular and maxillary measurements was considered, the accuracy for sex dimorphism was 85.7%. By using ratio variables, the accuracy was reduced to 68.9%. According to the findings of this study, total tooth length and root length are the most discriminant variables of canine teeth. These variables are more reliable sex indicators than crown measurements.

[A two-dimensional photographic and three-dimensional digital dental model comparative analysis in maxillary anterior teeth].

Objective: To assess the accuracy of two-dimensional (2D) photographs in measuring esthetic parameters of the maxillary anterior teeth by comparing them with measurements obtained from three-dimensional (3D) dental models. Methods: A total of one hundred volunteers (49 males, 51 females, aged 18-23 years) were recruited from School and Hospital of Stomatology, Wuhan University from January to February 2024. 3D digital models of their dentitions were obtained using an intraoral scanner, and standardized frontal 2D intraoral photographs were captured with a digital camera. The lengths, widths and width/length ratio of the bilateral incisors, lateral incisors and canines were measured on both the 3D digital models and the 2D intraoral photographs. The width ratios of adjacent maxillary anterior were also calculated on the 2D intraoral photographs and the frontal view of 3D digital models. Results: The widths of lateral incisors [(5.85±0.60) mm] and canines [(4.73±0.71) mm] and the lengths of canines [(8.72±0.96) mm] in the 2D intraoral photographs were significantly lower than those in 3D digital models [(6.65±0.59), (7.76±0.60), (8.90±0.86) mm] (t=-18.24, P<0.001; t=-54.43, P<0.001; t=-4.40, P<0.001), while there were no significant differences in the lengths and widths of the other teeth (P>0.05). The width/length ratios measured from the 2D intraoral photographs for the lateral incisors and canines (0.74±0.08, 0.55±0.08) were significantly lower than those measured in the 3D digital models (0.84±0.09, 0.88±0.09) (t=-19.68, P<0.001; t=-50.21, P<0.001), and the width/length ratio of the central incisors showed no significant difference between the two groups (P>0.05). The width ratios of canines/lateral incisors and lateral incisors/central incisors measured on the 2D intraoral photographs (0.72±0.06, 0.85±0.11) were significantly smaller than those measured in the frontal view of 3D digital models (0.75±0.06, 0.89±0.11) (t=-9.31, P<0.001; t=-6.58, P<0.001). Conclusions: There is a difference between 2D and 3D measurement results of teeth in the esthetic area and the magnitude of the difference varies with their position in the dental arch. When analyzing the measurement of the anterior teeth, it is necessary to choose the appropriate method according to the target tooth position.

Efficacy of electronic apex locators in comparison with intraoral radiographs in working length determination- a systematic review and meta-analysis.

BACKGROUND: Successful endodontic treatment needs accurate determination of working length (WL). Electronic apex locators (EALs) were presented as an alternative to radiographic methods; and since then, they have evolved and gained popularity in the determination of WL. However, there is insufficient evidence on the post-operative pain, adequacy, and accuracy of EALs in determining WL. OBJECTIVE: The systematic review and meta-analysis aims to gather evidence regarding the effectiveness of EALs for WL determination when compared to different imaging techniques along with postoperative pain associated with WL determination, the number of radiographs taken during the procedure, the time taken, and the adverse effects. METHODS: For the review, clinical studies with cross-over and parallel-arm randomized controlled trials (RCTs) were searched in seven electronic databases, followed by cross-referencing of the selected studies and related research synthesis. Risk of bias (RoB) assessment was carried out with Cochrane's RoB tool and a random-effects model was used. The meta-analysis was performed with the RevMan software 5.4.1. RESULTS: Eleven eligible RCTs were incorporated into the review and eight RCTs into the meta-analysis, of which five had high RoB and the remaining six had unclear RoB. Following meta-analysis, no significant difference in postoperative pain was found among the EAL and radiograph groups (SMD 0.00, CI .29 to .28, 354 participants; P value = 0.98). Radiograph group showed better WL accuracy (SMD 0.55, CI .11 to .99, 254 participants; P value = 0.02), while the EAL group had 10% better WL adequacy (RR 1.10, CI 1.03-1.18, 573 participants; P value = 0.006). CONCLUSION: We found very low-certainty evidence to support the efficacy of different types of EAL compared to radiography for the outcomes tested. We were unable to reach any conclusions about the superiority of any type of EAL. Well-planned RCTs need to be conducted by standardizing the outcomes and outcome measurement methods.

Three-dimensional evaluation of dental characteristics in patients with Cleidocranial dysplasia.

BACKGROUND: Cleidocranial dysplasia (CCD) is an autosomal dominant hereditary disorder. Besides skeletal abnormalities, CCD is often associated with dental complications, such as multiple supernumerary teeth and permanent teeth impaction or delayed eruption. METHODS: Supernumerary teeth of axial, sagittal and coronal CBCT view was characterized in detail and 3D image reconstruction was performed. Number and location of teeth, morphology of supernumerary teeth, positional relationship between supernumerary and adjacent permanent teeth, direction of supernumerary teeth in CCD patients were analyzed. RESULTS: The mean age of the 3 CCD patients in this study was 16.7 years. Among 36 supernumerary teeth, the majority of them were identified as apical side located and lingual side located. Normal orientation was the most common type in this study, followed by sagittal orientation, and horizontal orientation. Horizontal orientation teeth were all distributed in the mandible. Supernumerary teeth exhibited significantly shorter crown and dental-root lengths, as well as smaller crown mesiodistal and buccolingual diameters (P < 0.01). There was no difference in the number of supernumerary teeth between the maxilla and mandible, and the premolars region had the largest number of supernumerary teeth and the incisor region had the smallest number. CONCLUSIONS: This study compares number and location of teeth, morphology of supernumerary teeth, positional relationship between supernumerary and adjacent permanent teeth and direction of supernumerary teeth, this study also provides a reference for the comprehensive evaluation of CCD patients before surgery.

An Ex-Vivo Study Comparing the Accuracy of the E-Connect S+ and Morita Tri Auto ZX2+ Endodontic Handpieces in Root Canal Length Determination.

INTRODUCTION: This ex vivo study evaluated the accuracy of the Electronic Apex Locator (EAL) and Automatic Apical Stop (AAS) functions of the E-Connect S+ and Morita Tri Auto ZX2+ cordless apex locators in determining patency length. METHODS: Sixty-four human teeth with a single root were randomly allocated into E-connect or Morita groups (n = 32). The canals were accessed and preflared, after which a size 15 K-file was inserted into the canal to the major foramen and recorded as the actual length (AL). Matched measurements were taken using the AAS and EAL functions and visually confirmed with confocal microscopy. The variance between canal length (mm), the persons correlation (ρ) between function and AL, and the accuracy (%) of the canal length relative to the AL (Δmm) between devices and functions were assessed. RESULTS: Regardless of device or function, all measurements were within 1±Δmm and correlated strongly (ρ > 0.97) with the AL. When considering a more stringent clinically acceptable range of 0.5±Δmm from the AL, all devices and functions demonstrated similar accuracy levels (84%-94%). However, at lower tolerance ranges, the E-connect device with the EAL function exhibited the highest accuracy. On average, all devices and functions stopped short of the AL (mean Δmm>0). CONCLUSION: The E-Connect S+ and Morita Tri Auto ZX2+ apex locators provided reliable accuracy in determining the position of the major foramen. These findings demonstrate a high level of reproducibility in canal length measurements using both cordless endodontic handpieces, regardless of whether the EAL or AAS functions were employed.

Digital measurement of deciduous tooth dimensions in China: A cross-sectional survey.

OBJECTIVE: Crown dimensions data of deciduous teeth hold anthropological, forensic, and archaeological value. However, such information remains scarce for the Chinese population. This multi-center study aimed to collect a large sample of deciduous crown data from Chinese children using three-dimensional measurement methods and to analyze their dimensions. DESIGN: A total of 1592 children's deciduous dentition samples were included, and the sample size was distributed according to Northeast, North, East, Northwest, Southwest and South China. Digital dental models were reconstructed from plaster dental models. Independent sample t test, paired t test, principal component analysis (PCA), and factor analysis (FA) were used to analyze the tooth crown dimensions. RESULT: 18,318 deciduous teeth from 1592 children were included. Males exhibited slightly larger values than females. The range of sexual dimorphism percentages for each measurement was as follows: mesiodistal diameter (0.40-2.08), buccolingual diameter (0.13-2.24), and maxillogingival diameter (0.48-3.37). The FA results showed that the main trend of crown dimensions changes was the simultaneous increase or decrease in mesiodistal diameter, buccolingual diameter and maxillogingival diameter in three directions. CONCLUSION: This is the first large-scale survey of deciduous tooth crown dimensions in China, which supplements the data of deciduous tooth measurement and provides a reference for clinical application.

Can ultrasonography be used to determine working length in endodontic treatment? An in vitro study.

This study was conducted to evaluate efficacy of ultrasonography (USG) in determining working length in in-vitro conditions. Twenty five access cavities of maxillary incisor teeth were opened and actual working lengths (AWL) were measured with dental operating microscope. The working length were then measured with an electronic apex locator and USG. USG and apex locator measurements were statistically analyzed using one sample t-test and compared with AWL. The mean AWL measurment was 20.68 mm. USG measured the working length slightly longer (21.09 mm) than the measurements of apex locator (20.64 mm). Statistical analysis showed that the USG method provided similar measurements to electronic apex locators and with no statistical difference with actual working length (P < .05). USG emerges as a promising method for working length measurement that allows simultaneous visualization of root tip anatomy in cases where electronic apex locators may be insufficient and there is buccal cortical bone loss.

Frecuencia y tipología del segundo conducto mesiovestibular en primeros molares superiores / Frequency and typology of the second mesiobuccal canal in maxillary first molars

Objetivos: Evaluar mediante microscopia quirúrgica la presencia del segundo conducto mesiovestibular (MV2) en el piso de la cámara pulpar de los primeros molares superiores, determinar su abordabilidad, establecer el calibre de lima que llegó al tercio apical y tipificar radiovisiográficamente su morfología se-gún la clasificación de Weine. Materiales y métodos: Se utilizaron 48 primeros molares superiores huma-nos extraídos. Sé tomaron radiovisografías preope-ratorias (Carestream 5200) en sentido orto radial y mesio-distal. Se realizó apertura y se localizó entra-da del MV2 con microscopio quirúrgico (Newton MEC XXI, Argentina) a 16 x. Se cateterizó MV1 y MV2 con limas tipo K #10 y #15 (Dentsply Maillefer). Se cortó raíz distovestibular para mejorar visualización ra-diovisográfica. Se tomó conductometria en sentido mesio-distal para establecer la tipología. Se compa-raron frecuencias y porcentajes mediante test de Chi-cuadrado con corrección de Yates, prueba exac-ta de Fisher y test z para diferencia de proporcio-nes. Se calcularon intervalos de confianza 95% para porcentajes mediante método score de Wilson. Re-sultados: El 54% (26 casos) presentó MV2. De los 26 MV2, el 77% (20 casos) fueron abordables, porcen-taje significativamente mayor al 23% no abordable (z=3,62; P<0,05). Al hacer cateterismo, hubo asocia-ción significativa entre tipo de conducto (MV1 y MV2) y calibre de lima que llegó al tercio apical (Chi-cua-drado=29,12; gl=1; P<0,05). La tipología I (58%) fue significativamente mayor que las tipologías II (21%) y III (21%) (P<0,05 para ambas comparaciones). Con-clusión: El alto porcentaje de piezas que presentó MV2 evidencia la importancia clínica de detectarlo y tratarlo correctamente. Dado el alto porcentaje de piezas donde fue abordable, se concluye que el clíni-co debe tener conocimiento, destreza y la tecnología necesaria para poder abordarlo. Si bien la tipología I (58%) fue la más encontrada, cuando el MV2 termina en foramen independiente (tipo III), su omisión puede conducir al fracaso del tratamiento (AU))

Objectives: To evaluate by surgical microscopy the presence of second mesiobuccal canal (MB2) in the pulp chamber floor of the maxillary first molars, determine its approachability, establish the caliber of the file that reached the apical third, and radiographically typify its morphology according to Weine ́s classification. Materials and methods: 48 extracted human maxillary first molars were used. Preoperative radiovisographies (Carestream 5200) were taken in ortho-radial and mesio-distal direction. Coronal access was made and the entrance of MB2 was located with a surgical microscope (Newton MEC XXI, Argentina) at 16x. MB1 and MB2 were catheterized with K files #10 and #15 (Dentsply Maillefer). Distobuccal root was cut to improve radiovisographic visualization. Conductometry was taken in mesio-distal direction to establish the typology. Frequencies and percentages were compared using Chi-square test with Yates correction, Fisher's exact test and z test for difference in proportions. 95% confidence intervals were calculated for percentages using Wilson score method. Results: 54% (26 cases) presented MB2. Of the 26 MB2, 77% (20 cases) were approachable, a significantly higher percentage than those not approachable (z=3.62; P<0.05). When performing catheterization, there was a significant association between type of canal (MB1 and MB2) and file caliber that reached the apical third (Chi-square=29.12; df=1; P<0.05). Typology I (58%) was significantly higher than typologies II (21%) and III (21%) (P<0.05 for both comparisons). Conclusion: The high percentage of specimens that showed MB2 evidence the clinical importance of detecting and treating it correctly. Given the percentage of pieces where it was approachable (77%), it is concluded that the clinician must have the knowledge, skill and necessary technology to be able to approach it. Although typology I (58%) was the most found, when MB2 ends an independent foramen (type III), its omission can lead to treatment failure (AU)

Correlation between head circumference and mesio-distal width of the maxillary central incisor: a cross sectional study among three different population groups.

The size and shape of a tooth vary between individuals of different ethnic groups and genders because of the influence of different genetic factors. The information regarding the different anatomical factors using maxillary anterior teeth is very scanty. Thus to give more clarity, a study was planned to assess the correlation between head circumference and tooth-mesiodistal width among children of different ethnic origins.The study was carried out on 210 children aged 7 to 12 years in schools at Abha, Saudi Arabia.The mesiodistal (MD) width of the central incisor was measured using a digital vernier caliper. A Meter tape ruler was used to measure the Head/Cephalic dimensions. The data obtained were subjected to statistical analysis using IBM SPSS 20.0, and the results were analyzed. It was found that mean MD tooth width and head circumference were maximum in Saudi children, followed by South Asian and Arab/African, with an insignificant statistical difference (p-value > 0.05). Correlation between MD dimensions of maxillary central incisor with head circumference was statistically significant (p-value < 0.05) among Saudi and South Asian populations, whereas statistically insignificant (p-value > 0.05) difference between Saudi and Arab/African populations. It was concluded that there exist the ethnic differences between tooth-mesiodistal width and head circumference dimensions of children. A positive correlation between head circumference and mesiodistal width of the central incisor was determined.

Geometric analysis of tooth size among different malocclusion groups in a Hispanic population.

INTRODUCTION: Tooth size ratio is important for optimal dentofacial esthetics, occlusal interdigitation, and postorthodontic treatment stability. Tooth geometry influences tooth size ratio; therefore, tooth size normative data may not be practical across diverse ethnic groups. This study aimed to determine whether there are significant differences in 3-dimensional tooth size among patients in the Hispanic population with Angle Class I, II, and III malocclusions. METHODS: The data were collected using intraoral scanned orthodontic study models representing Hispanic orthodontic patients with Angle Class I, II, and III malocclusions. The scanned models were digitized and transferred to a geometric morphometric system. Tooth sizes were determined, quantified, and visualized using contemporary geometric morphometric computational tools. RESULTS: Tooth size was determined for all teeth and showed a significant difference in 4 out of 28 teeth: Maxillary right first molar, mandibular left second molar, mandibular right first molar and mandibular right second molar. This significant difference was noted among females and affected different malocclusion groups. CONCLUSIONS: Tooth size discrepancy in the Hispanic population varies among malocclusion groups, and the variation is determined by the participant's gender.

Maxillary lip dynamics and gingival display revisited: Utilizing standardized metrics.

OBJECTIVE: This study was initiated to validate a predictable system for establishing maximum maxillary lip dynamics and highlight the clinical significance of the findings. MATERIALS AND METHODS: Seventy-five subjects, ranging in age from 25 to 71 years old were photographed with lips in maximum and minimum reveal. The images were digitally analyzed using set references. The statistical analysis was performed using Meta. Numerics version 4.1.4. A Pearson correlation coefficient (r) was carried out to identify relationships between age and maxillary lip dynamics. A p-value less than or equal to 0.05 was considered to be significant. RESULTS: A greater percentage of participants have posterior gingival display than anterior gingival display. There is greater movement of the maxillary lip at the cuspid than at the central incisor. CONCLUSION: There was a tendency for lip dynamics to increase at the right central incisor when there is an increase in lip dynamics at the right cuspid. Lip dynamics does not appear to decrease with age. CLINICAL SIGNIFICANCE: Accurately recording and considering maximum lip dynamics helps avoid asymmetric, excessive or insufficient gingival architecture, insufficient or excessive tooth length and visible restorative margins.

Using a digital platform to establish odontometric variation based on race, gender and Angle classification.

Orthodontists often encounter significant clinical challenges in the finishing stages of treatment due to a disproportion in interarch tooth size relationships. Despite the increasing presence of digital technology and concomitant focus on customized treatment approaches, there is a gap in the knowledge of how generating tooth size data using digital versus traditional methods may impact our treatment regime. OBJECTIVE: This study aimed to compare the prevalence of tooth size discrepancies using digital models and a digitally based cast analysis in our cohort based on (i) Angle's Classification; (ii) gender and (iii) race. MATERIALS AND METHODS: The mesiodistal widths of teeth in 101 digital models were assessed using computerized odontometric software. A Chi-square test was used to determine the prevalence of tooth size disproportions among the study groups. The differences between all three groups of the cohort were analysed using a three-way analysis of variance (ANOVA). RESULTS: An overall Bolton tooth size discrepancy (TSD) prevalence of 36.6% was observed in our study cohort; 26.7% had an anterior Bolton TSD. No differences existed in the prevalence of tooth size discrepancies between male and female subjects as well as between the different malocclusion groups (P > .05). Caucasian subjects had a statistically significant smaller prevalence of TSD compared to Black and Hispanic patients (P < .05). CONCLUSION: The prevalence results in this study illuminate how relatively common TSD is and underscores the importance of proper diagnosis. Our findings also suggest that racial background may be an influential factor in the presence of TSD.

Polymorphisms in hormonal-related genes might be associated with variations in permanent tooth crown size.

BACKGROUND: The variability in tooth crown size (TCS) is influenced by genetic factors and might be regulated by the difference in hormonal response. MATERIALS AND METHODS: This study aimed to evaluate the association between variations in TCS of permanent teeth with associated factors and genetic polymorphisms in hormonal-related genes (ESR1, ESR2 and PTH). This cross-sectional study involved dental casts from 86 individuals of both sexes. Dental casts were used to determine the maximum TCS of all fully erupted permanent teeth (except third molars) in the mesiodistal (MD) and buccolingual (BL) dimensions. Data such as sex, ethnicity, dental group (incisor, canine, premolar and molar), dental arch (upper and lower) and genetic polymorphisms of hormonal-related genes were used. The DNA from each patient was collected to evaluate the genetic polymorphisms in ESR1 (rs2234693 and rs9340799), ESR2 (rs1256049 and rs4986938) and PTH (rs694, rs6256 and rs307247) through real-time PCR. The data were submitted to statistical analysis with a significance level of 0.05. RESULTS: In the MD dimension, the sex, dental group and dental arch were associated with variation in TCS (P < .05). In the BL dimension, the sex, dental group, dental arch and polymorphism in rs694 and rs307247 were associated with variation in TCS. CONCLUSIONS: In short, this study suggests that genetic polymorphisms of PTH are associated with variations in the BL TCS of permanent human teeth.

Size estimation of unerupted canines and premolars using various independent variables: a systematic review.

INTRODUCTION: Prediction of unerupted permanent teeth is an essential part of orthodontic diagnosis and treatment planning. This prediction is done by mixed dentition space analysis based on the estimation of mesiodistal dimensions of unerupted permanent canine and premolars from already erupted permanent teeth. Permanent mandibular incisors are most commonly used for prediction. Recent literature reveals that mandibular incisors are not accurate predictors and other independent variables have been introduced to make a more accurate and precise prediction. The objective of this paper was to evaluate the literature in light of a variety of independent variables and their predictive accuracy. METHODS: Electronic databases such as MEDLINE, PubMed, Scopus, Embase, Web of Science, CINAHL Plus were searched to identify articles published until September 2021. RESULTS: The search resulted in a total of 1098 articles, of which 24 papers met our inclusion criteria and were included in this review. Articles using permanent mandibular incisors only as a predictor were excluded during the eligibility assessment. The results show that various independent variables including mesiodistal and vestibulo-oral dimensions of permanent maxillary and mandibular incisors and molars, molar basal arch length, intermolar distance, maxillary and mandibular arch and gender have been used as predictors to more accurately determine mesiodistal width of unerupted canine and premolars in different populations. CONCLUSION: Ethnic tooth size variations strongly emphasize the need to determine which independent variable gives a more accurate prediction of unerupted permanent teeth to develop a population-specific prediction model. This will play a significant role in managing space problems and developing malocclusions.

Working length determination in primary teeth pulpectomy: A systematic review and meta-analysis.

The present meta-analysis aimed to describe the methods to determine the working length in primary teeth pulpectomy, also evaluating and comparing their reliability. A systematic review was performed following the PRISMA Statement. The electronic search was conducted on PubMed, Scopus, Cochrane Library and Web of Science. After the screening protocol, a number of 14 studies were included in the qualitative analysis, while seven were included in the quantitative one. The mean working length determined by the electronic apex locator was 11.8 mm (9.0-15.55), while 12.42 mm (11.0-13.52) and 12.3 mm (9.73-15.93) were the mean working length observed with the conventional radiography and the digital radiography, respectively. No statistically significant difference was detected in quantitative analysis between the investigated methods. The present meta-analysis showed that electronic apex locator, conventional radiography and digital radiography are similar in determining working length in primary teeth.

Accuracy of the KontrolFlex AccuFile when used with the Root ZX electronic apex locator in vitro.

The aims of this study were to determine the efficacy of the KontrolFlex™ Accufile™ compared to the READY•STEEL™ Flexofile® using an electronic apex locator and to evaluate the instrument's design via scanning electron microscopy. Actual canal lengths of 30 extracted teeth were determined under magnification. An alginate model was used to determine experimental canal lengths with the Root ZX II apex locator (EAL) and size #10 Accufiles and Flexofiles. Differences between actual lengths and experimental lengths were compared with Student's t test. The average experimental lengths were short of the actual length by -0.10 mm (±0.34) and -0.12 mm (±0.16) for the Accufile and Flexofile, respectively with no statistical difference (p > 0.05). SEM images revealed similar non-cutting Batt tips and a square cross-section for the Accufile and triangular for the Flexofile. Both files provided similarly high levels of reliability when used with the Root ZX II EAL.