Maxillary and mandibular tooth size in different racial groups and in different occlusal categories

Radiculomegaly as a key clinical feature in oculo-facio-cardio-dental (OFCD) syndrome: a case report with a novel truncating variant in BCOR gene

Radiculomegaly is a rare dental anomaly characterised by the enlargement of the root canals of teeth. It is usually associated with oculo-facio-cardio-dental (OFCD) syndrome due to truncating variants in BCL-6 transcriptional corepressor (BCOR) (MIM*300485). We present the case of a 21-year-old female patient who was referred to genetics for a polymalformative syndrome including bilateral glaucoma and dental anomalies, especially radiculomegaly. Some others dysmorphic features were right superior lip notch, ogival palate, long philtrum, difficulty in pronation, café-au-lait spots, II-III toe bilateral syndactyly, and macrocephaly. Cone-beam CT confirmed radiculomegaly. The genetic analysis identified a heterozygous pathogenic variant NM_001123385.1:c.2093del (p.Pro698Glnfs*17) in the BCOR gene. After genetic diagnosis of OFCD syndrome, cardiac CT-scan revealed a large asymptomatic atrial septal defect that was subsequently surgically closed. Reviews of the literature have previously highlighted the prevalence of radiculomegaly in OFCD syndrome with a positive predictive value of 88.23% and a sensitivity of 75.94%. This case report highlights the importance of radiculomegaly as a clinical sign of OFCD syndrome, emphasising the rarity of non-syndromic radiculomegaly and the benefits of its diagnosis in clinical management, especially in cardiac screening.

Digital analyses of Bolton tooth size ratios and their association to gender, angle class, and other occlusal traits: a study using a partially automated digital 3D model analysis

BACKGROUND

This study aims to verify Bolton's values for tooth size ratios and to evaluate possible relationships to different occlusal traits using precise digital measurement methods.

MATERIALS AND METHODS

Including 1000 consecutively selected patients from three study centres a digital, partially automated model analysis was performed utilizing the software OnyxCeph. The measurements comprised tooth width for calculation of anterior (AR) and overall ratio (OR) as a percentage, arch width, length, perimeter, overjet, overbite, space analysis in millimetre and the assessment of the angle classification.

RESULTS

AR and OR were significantly increased compared to Bolton's ratios of 77.2% (AR) and 91.3% (OR). In the gender comparison, male patients showed larger tooth size ratios, especially in the OR. Patients with Angle Class II/1 and II/2 had smaller tooth size ratios than patients with Angle Class III and I. Thus, patients with Angle Class II/1 had the largest tooth diameters in all maxillary teeth and with Angle Class II/2 the smallest tooth sizes in the mandible. The largest tooth widths in the lower jaw were observed in the Angle Class III patient group. Furthermore, a negative correlation from AR/OR to overjet, overbite, and available space in lower jaw as well as a positive correlation to available space in upper jaw was detected.

CONCLUSIONS

There is a clear correlation between the tooth size ratios and the present dysgnathia as well as other orthodontically relevant occlusal traits. This prior knowledge about our patients is extremely important to create an individualized treatment plan and enable sufficient occlusion. To achieve a functionally good occlusion with correct overjet and overbite, it is essential that the maxillary and mandibular teeth are proportional in size. Any deviation from the ideal patient in terms of tooth size, number, shape, or arch must be considered in the pre-therapeutic treatment plan in combination with the existing dysgnathia in order to be able to achieve a stable anterior and posterior occlusion with appropriate adjustments to the therapy post-therapeutically.

Reliability of Moyer's and Tanaka Johnston's prediction methods in a non-Caucasian heterogeneous population - a cross-sectional study

INTRODUCTION

Mixed dentition analyses are used to determine possible tooth-size and arch-length discrepancies during the transition from primary to permanent dentition. Prediction methods using a probability table or linear regression equation use the sum of the mesiodistal widths of mandibular permanent incisors to predict the mesiodistal width of unerupted permanent teeth. Racial and sexual variations and sexual dimorphism in tooth size have been reported. The objective of this study is to validate Moyer's and Tanaka Johnston's mixed dentition analyses in a contemporary South Indian population.

An analysis of maxillary anterior teeth dimensions for the existence of golden proportion in the representative North Indian population

Context

Esthetic appearance of the face is a major concern in self-image among the majority of the population. The dimensions, anatomy, and arrangement of maxillary anterior are the key factors in the esthetic appearance of the face.

Aim

The present study aimed to measure the mesiodistal dimensions of maxillary anterior teeth and analyzing the golden proportion in the representative North Indian population.

Materials and Methods

Subjects were seated in the upright position in a dental clinical chair. A digital Vernier caliper was used to record the mesiodistal dimensions of central incisors (CIs), lateral incisor (LI), and canine (C) teeth in maximum smile position. A total of three sets of recordings were made by a single observer to avoid the measurement bias of both left and right sides of teeth. Digital images were also captured. Obtained measurements were used for the calculation of ratios and statistical analysis was done.

Results

The prevalence of golden ratio between right CI/LI was observed in 3.1% males and 3.2% females. The calculated median ratio was 1.2 for males and 1.3 for females which differs significantly (P > 0.05) from the golden ratio. The divine proportion between visible portion of right C/LI was seen in 39.5% males and 32.3% females with calculated median value for males being 0.6 and that for females was 0.7.

Conclusion

The prevalence of golden proportion between the CI/LI in esthetically pleasing smiles was too small (mean-3.9 in males and 2.75 in females) while the golden ratio of 0.6 was found in the majority of the population irrespective of the gender.

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.

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.

Evaluation of the anterior and overall tooth ratios in the Saudi population versus Bolton's standards

Understanding tooth-size discrepancy is essential in the process of diagnosis of maxillary and mandibular relationship. Due to the high incidence of tooth-size disproportion, Practitioners should consider the high incidence of tooth-size disproportion when planning treatment for their patients, as in many cases, this can be a hindrance to obtaining an ideal result. This study aimed to determine the anterior and overall tooth ratios in the Saudi population and compare them with Bolton's standards. A total of 356 patients were recruited. For the anterior ratio, around 25% of the patients had a ratio equal to Bolton's standards (77.2%). Most subjects (53.7%) had a ratio above 77.2%, and the remaining (20%) had a ratio below 77.2%. The mean amount of anterior mandibular excess was 2.17 ± 2.12 mm, and the mean amount of anterior maxillary excess was 2.16 ± 2.08 mm. For the overall ratio, less than half of the participants (43%) had a ratio equal to Bolton's standards (91.3%). Almost 34% had a ratio above 91.3%, while 23% of the participants had a ratio below 91.3%. The mean amount of overall mandibular excess was 2.54 ± 2.37 mm, and the mean amount of overall maxillary excess was 3.31 ± 3.33 mm. The majority of the study sample had an overall and anterior Bolton ratio that is different from the norms of Bolton's standards, with a tendency for increased overall and anterior ratios. Having specific standards for the Saudi population is important for better clinical assessment and treatment outcomes.

Morphometric analysis of tooth morphology among different malocclusion groups in a hispanic population

BACKGROUND

There have been reports of unique dental morphological features amongst Latin American and Hispanic populations, and this might invalidate the use of current orthodontic diagnostic tools within this population. There are no tooth size/tooth ratio normative standards for the Hispanic population, despite overwhelming evidence about differences in tooth size between racial groups.

OBJECTIVE

This study aimed to determine whether there are significant differences in 3-D tooth shape between patients with Angle Class I, Class II, and Class III dental malocclusion in the Hispanic population.

METHODOLOGY

Orthodontic study models representing Hispanic orthodontic patients with Angle Class I, II, and III dental malocclusions scanned using an intra-oral scanner. The scanned models were digitized and transferred to a geometric morphometric system. Tooth size shape were determined, quantified, and visualized using contemporary geometric morphometric computational tools using MorphoJ software. General Procrustes Analysis (GPA) and canonical variates analysis (CVA) used to delineate the features of shape that are unique to each group.

RESULT

The study revealed differences in tooth shape between the different dental malocclusion groups on all twenty-eight teeth that were studied; the pattern of shape differences varied between the teeth and the dental malocclusions. The MANOVA test criteria, F approximations, and P-values show that shape in all the groups was significantly different < 0.05.

CONCLUSION

This study revealed differences in tooth shape between the different dental malocclusions on all teeth, and the pattern of shape differences varied between the different dental malocclusions group.

Effects of Low-Level Laser Therapy on Orthodontic Tooth Movement: Evaluation of Bony Changes via 3DCBCT

OBJECTIVE

The prime objective of this research was to study the effect of low-level laser therapy (LLLT) with an evaluation of bony changes via pre- and post-treatment 3DCBCT in orthodontic malocclusion cases treated with fixed orthodontic appliances.

MATERIALS AND METHODS

Subjects who attended the Orthodontic Clinic, were diagnosed with orthodontic malocclusion, treated with fixed orthodontic appliances, and had pre- and post-management CBCT were included in the study. Patients aged 14 to 25 years who met the inclusion criteria were assigned to two groups, group A (LLLT) and group B (non-LLLT). Group A participants were treated with LLLT therapy as per standard protocol after explaining the nature of the treatment. Group B (non-LLLT) participants were not treated with LLLT therapy and therefore served as the control. LLLT was used in the experimental group after placing each archwire. Interradicular bony changes at depth levels of 1 to 4 (2, 5, 8, and 11 mm) using 3DCBCT were measured as outcome parameters.

RESULTS

The information collected was analyzed using SPSS computer software. Mostly insignificant differences were noted among groups for the different parameters (p < 0.05). Student's t-tests and paired t-tests were used to investigate the differences. Experimental Hypothesis: There will be significant differences in the interradicular width (IRW) measurements between the LLLT and non-LLLT groups.

CONCLUSIONS

The hypothesis was rejected. Upon investigation of prospective changes, most of the measured parameters showed insignificant differences.

Golden Mean and Proportion in Dental Esthetics after Orthodontic Treatments: An In Vivo Study

PURPOSE

The definition of the golden ratio was established around the sixth century BC; Levin and Snow developed specific theories applicable in dentistry, which apply the golden proportion rule with the intention of reproducing a perfect smile. This study analyzed the literature and assessed whether these concepts remain valid and applicable in clinical practice, evaluating the theories with a group of patients followed by an experienced orthodontic team.

METHODS

This study was retrospectively performed on 400 patients (241 females and 159 males) who underwent orthodontic treatments. The analysis was conducted on intraoral frontal photos, both pre-treatment and post-orthodontic treatment, to observe if there was a statistically significant difference in the tooth display according to the golden mean and golden proportion theories.

RESULTS

The canine at the end of the orthodontic treatment had a greater visibility than that proposed by Levin and Snow.

CONCLUSIONS

This study revealed how these theories could be considered in certain respects, but nowadays are not totally valid and applicable to the clinical reality. Snow's theory appears to be more consistent with the clinical findings than Levin's theory.

A simple method for quick evaluation of the anterior tooth ratio: an observational study

Background

An ideal relationship of anterior teeth is closely related to postoperative function, stability, and aesthetics. Therefore, it is necessary to estimate the proportion of anterior teeth when communicating with patients about possible treatment plans and outcomes. This study aimed to establish a simple method for assessing the proportion of anterior teeth and to identify the standard ratio value to provide references for clinical work.

Methods

Five hundred fourteen patients were divided into derivation, standard, and validation datasets. We first deduced our novel simplified anterior tooth ratio (SATR) by finding the key teeth with the derivation datasets, then established standard values by measuring the standard models, and finally validated the diagnostic performance of SATR. Independent sample t-test was used to select key teeth. Pearson’s correlation analysis and linear regression analysis was used to test and verify the correlation between SATR and the anterior Bolton ratio. Chi-square test and diagnostic test were used to verify the diagnostic results using SATR. P values of < 0.05 were considered statistically significant.

Results

Patients with an abnormal anterior Bolton ratio were more likely to have variations in the maxillary and mandibular lateral incisors. Therefore, the ratio of maxillary and mandibular lateral incisors was chosen as a simple way to assess the anterior tooth ratio and was defined as SATR (simplified anterior tooth ratio). A positive correlation was observed between SATR and anterior Bolton ratio (r = 0.702, p < 0.001), with the linear regression equation as follows: y = 0.503 + 0.328x, x = SATR, y = anterior Bolton ratio. The standard value of SATR was established (85.69% ± 3.57%) and proven reliable in clinical practice.

Conclusions

The ratio of maxillary and mandibular lateral incisors can be used to estimate the anterior tooth ratio, which showed high reliability and efficiency.

Tooth size discrepancy in orthodontic patients with skeletal anterior open bite

OBJECTIVE

To find out if there is any relationship between tooth size discrepancy (TSD) and skeletal anterior open bite (AOB) and to assess the correlation between the amount of AOB and TSD.

METHOD

A total of 100 Class I subjects were included in this study (average age 15.21 ± 2.84 years). Fifty patients had skeletal AOB (>3 mm) and 50 subjects acted as controls and had a normal overbite. Teeth mesio-distal widths were measured using a digital caliper. Anterior, overall, and posterior TSD ratios were calculated. An independent t-test was employed to assess differences between groups and between genders. Pearson correlation coefficient was used to assess the correlation between the amount of AOB and TSD.

RESULTS

Significant differences in anterior (p = .038) and posterior (p = .015) TSD ratios were detected. In the skeletal AOB group, no significant gender differences were detected (p > .05), whereas in the normal bite and total sample group, males had smaller posterior teeth compared to females (p < .05). All the differences were smaller than 1 SD of Bolton's ratios. No significant correlation was found between the amount of AOB and TSD ratios (p > .05).

CONCLUSIONS

Skeletal AOB had larger anterior and smaller posterior mandibular teeth, but the differences were less than 1 SD of Bolton's ratios. Males have smaller mandibular posterior teeth than females. The amount of AOB is not correlated with the TSD ratios.

Computed Tomography-Based Investigation on the Effects of Intravenous Bisphosphonate Administration on Tooth Growth in a Minipig Animal Model

Background and Objectives: The objective of this study was to evaluate the effects of bisphosphonate (BP) administration on tooth growth, using CT-data of a minipig animal model investigation. Materials and Methods: Tooth growth was evaluated in minipigs, with eight animals receiving weekly zoledronate (ZOL) and three animals serving as the control group. Tooth growth was evaluated at the right 2nd molar (M2) in the maxilla. A computed tomography-based measuring method was applied to evaluate tooth growth in the coronal-apical, buccal-oral and mesial-distal axis. Results: ZOL-administration was found to impact tooth growth in all evaluated measuring axes, with the highest effect observed in the coronal-apical axis. Conclusions: Detrimental effects of BP administration on growing teeth have been reported by a number of investigators. The results of this investigation demonstrate that intravenous ZOL affects the growth of the whole tooth within a short period of administration. With BPs being administered to a growing number of pediatric patients, further studies should be conducted to qualify and quantify the effects of BPs on developing teeth.

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.

Crown dimensions of primary teeth-A systematic review and meta-analysis

Odontometrics, also known as metric traits, includes mesiodistal, buccolingual dimensions, and crown height. The purpose of this study was to assess pancontinental odontometric variations in the crown dimensions of primary teeth. Ten electronic databases were searched to identify studies that measured crown dimensions of primary teeth, published in English language, without year restriction up to July 2020. Studies included cross-sectional research measuring on casts, subjects, and on radiographs of healthy children. Meta-analysis was performed, and risk of bias was assessed using modified Newcastle-Ottawa Scale. Eighty-seven observational studies were included, with 24,634 participants (9487 males, 11,083 females; 19 studies lacked gender information). Only one study showed a low bias risk, whereas 81 and 5 studies had moderate and high risk, respectively. Sixty-five studies included for meta-analysis revealed heterogeneity in mean mesiodistal dimensions of maxillary first molars from Asia (I² -99.7%), buccolingual measurements of mandibular first molars from Europe (I² -99.9%), crown height of mandibular second molars from Africa and Europe (I² -79.8%). Among mesiodistal and buccolingual dimensions, Australians have larger while Asians have smaller teeth. Pertaining to crown height, very few studies could be found in the literature. This review highlights the variations in crown dimensions of primary teeth among populations.

Associations between Bolton ratio and overjet deviations in a Finnish adult population

OBJECTIVE

To determine the anterior Bolton ratio for a Finnish adult population and to investigate its associations with overjet.

MATERIAL AND METHODS

This study is part of the Northern Finland Birth Cohort 1966. Clinical oral investigations, including three-dimensional intraoral scanning and registration of occlusion, were performed in connection with the 46-year follow-up for 1,961 subjects. Subjects with normal occlusion (n = 149), extreme overjet ≥ 8 mm (n = 49), large overjet 6-7 mm (n = 86), and negative overjet (n = 16) and no orthodontic treatment history were selected for further analysis. The mesiodistal widths were measured from canine to canine to evaluate the anterior Bolton ratio.

RESULTS

A mean anterior Bolton ratio of 78.6 (SD 3.1) was found for the normal occlusion group. Subjects with extreme overjet had smaller Bolton ratios compared to the normal occlusion group and the negative overjet group (p = .005, p = .019, respectively). Overjet deviations were associated with upper canine and incisor widths.

CONCLUSIONS

The mean anterior Bolton ratio in subjects with normal occlusion was larger compared to the original Bolton ratio. Tooth size discrepancy was associated with extreme and negative overjet at population level.

Evaluation of the golden proportion in the natural dentition: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Different proportions of tooth width ratios have been evaluated, and the golden proportion is the best known. Although the prevalence of the golden proportion has been evaluated in different ethnic groups and populations, a meta-analysis of these studies is lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to investigate the existence and suitability of the golden proportion for tooth width ratios and to assess the prevalence of the golden proportion among populations.

MATERIAL AND METHODS

A systematic search based on the Patient, Intervention, Comparison, Outcome (PICO) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted in PubMed, Cochrane, Scopus, Web of Science, and Embase in January 2021 without any time limitations and included English and non-English-language articles. Additional studies were identified by searching the reference lists of the retrieved articles. Two reviewers independently performed the literature search and data extraction, selecting articles based on the inclusion and exclusion criteria. Eligible studies were selected based on the inclusion criteria, and quality assessments were conducted. Descriptive statistics were applied for a number of outcome measures. Using a meta-analysis software program, data extracted from each selected study were statistically combined by using weighted mean differences and 95% confidence intervals, and heterogeneity was calculated for each measurement.

RESULTS

A total of 566 articles were retrieved based on the keyword search. After the articles were assessed based on the inclusion and exclusion criteria, only 6 articles were included in the meta-analysis.

CONCLUSIONS

The outcomes of the review and analyses demonstrate that evidence supporting the existence of the golden proportion in natural smiles is lacking and that the existence of the golden proportion in dentistry is a myth and not a fact. However, the golden percentage theory can be applied with modified percentages that consider critical aspects of esthetic dentistry.

Evaluation of Dental Golden Ratio in Terms of Facial Esthetics

Aim and Objectives:

This cross-sectional study examined the Bolton index of 6 maxillary anterior teeth and the facial esthetic ratios in the Turkish population with healthy facial appearance.

Materials and Methods:

Face photographs of the subjects, taken using a DSLR camera, were fixed in the Frankfort horizontal plane. The measurements were made on the images using ImageJ 1.52a software and certain ratios of face and teeth were calculated such as Bolton index (BI). Differences between genders were evaluated and comparisons with golden ratio of 1.618 were conducted on SPSS.

Results:

Males had significantly higher upper, middle, lower, and total facial height compared to females ( P < .001, P = 0.0257, P = .0243, P < .001, respectively). Right to left distance of labial commissure (LC)/distance from the distal edge of right canine to the distal edge of left canine ratio had golden proportion. Ratio of naso-menton length to facial width showed golden ratio only in males. The ratio of the width of upper middle incisor to the width of canine tooth also showed golden ratio in both genders.

Conclusions:

The present study presents noteworthy data about facial and teeth ratios of the young adult Turkish population that will guide plastic surgeons and orthodontists in clinical practice.

The Tooth Size Discrepancy among Orthodontic Patients and Normal Occlusion Individuals from Saudi Arabia: A Three-Dimensional Scan Analysis of Diagnostic Casts

Background/Purpose:

Tooth size discrepancy is one of the causative factors of malocclusion. This study aimed to establish the TDS among various malocclusion classes and normal occlusion subjects in a Southern Saudi population.

Materials and Methods:

The study casts of orthodontic patients from Southern Saudi Arabia (mean age: 19.6 years ± 2.45; n = 120) were randomly selected and grouped into eight equal classes based on Angle's classification and gender. An additional 30 study casts, devoid of malocclusion, having excellent intercuspation and class I occlusion, were grouped into two controls (n = 15) based on gender. The study casts were three-dimensional scanned to measure mesiodistal widths of all the teeth. The calculated anterior ratios (AR) and overall ratio (OR) were statistically analyzed with analysis of variance and t-tests.

Results:

There were no significant differences in “OR” and “AR” between the genders (P > 0.05) and among the malocclusion and control subgroups (P > 0.05). The mean “OR” (92.01 ± 0.18) and “AR” (78.60 ± 0.27) of the malocclusion group were significantly higher than that of Bolton's ratios (P > 0.05). The “AR” of the control group was significantly higher than Bolton's standards (P = 0.048). However, “OR” was no different (P = 0.105). Malocclusion patients displayed a discrepancy (±2 standard deviation) in “AR” of 22.5% and 'OR' of 6.7% from Bolton's mean (BM). Similarly, the control group displayed a discrepancy in “AR” of 20% and “OR” of 10% from BM.

Conclusion:

The mean “OR” and “AR” of the Southern Saudi population showed no sexual dimorphism and no significant difference among various malocclusion and control subgroups. The “AR” of the malocclusion and control subgroups did not comply with Bolton's standards.

Craniofacial characteristics of Syrian adolescents with Class II division 1 malocclusion: a retrospective study

Background

Malocclusion characteristics vary across different ethnic groups and populations. Limited data are available regarding the characteristics of Syrian adolescents with Class II division 1 (Class II-1) malocclusion, and the recent inflow of Syrian refugees and immigrants into Europe and many areas worldwide demonstrate the need for updated studies to discover the craniofacial characteristics of these new immigrants.

Objectives

The present compound cephalometric and tooth-size study sought to assess the dentofacial morphology, upper-airway dimensions, and tooth-size characteristics of Syrian adolescents with Class II-1 malocclusion and compare the results with established Syrian population norms.

Materials and Methods

The study sample consisted of 43 Syrian patients including 24 females and 19 males with Class II-1 malocclusion (age: 14.3 (±1.5) years, mean (±SD)). Cephalometric radiographs and orthodontic casts were analyzed using special orthodontic software (OnyxCeph3^™) and a universal digital caliper, respectively. Statistics were calculated using the SPSS software.

Results

In Syrian adolescents with Class II-1 malocclusion, the position of the mandible relative to the nasion perpendicular (mean (95% confidence interval)) was −11.01 (−12.45, −9.57) mm. Facial axis angle showed a negative value: −6.25 (−7.65, −4.85) degrees. An obtuse nasolabial angle was observed: 104.05 (101.77, 106.33) degrees. The average width of the upper pharynx was 11.50 (10.53, 12.47) mm; however, there was no prevalence of an upper-pharyngeal width of 5 mm or less. The average value of the anterior tooth-size ratio was 80.69 (79.85, 81.53) percent. In total, 39.5% of the investigated subjects had anterior ratios outside two standard deviations from Bolton’s norm, while 25.6% of the investigated subjects had anterior ratios outside two standard deviations from Syrian population norm.

Conclusions

In this study, the inter-maxillary discrepancy of Class II-1 Syrian adolescents was a consequence of their hyperdivergent facial pattern. The observed small pharyngeal widths were not clinically significant, while the anterior tooth-size discrepancy might be clinically relevant.

Evaluation of influence factors on the width, length, and width to length ratio of the maxillary central incisor: A systematic review and meta-analysis

OBJECTIVES

The aim of this study was to analyze whether symmetry of left and right sides, gender, measuring method, and ethnicity have influences on width (W), length (L), and width to length ratio (W/L) of the maxillary central incisor (MCI) and provide a reference for dental treatment planning in the esthetic zone.

MATERIALS AND METHODS

An electronic search was conduct of the dental literature. Studies reporting data about measurements were included. Data were extracted and analyzed for the differences between left and right, male and female, different measuring methods, and ethnicities by Review Manager and Stata statistical software.

RESULTS

Seventeen studies were included. There were no differences between measurement of the left and right groups, perceived and actual measuring groups. However, differences were found between genders in MCI's W and L but no difference in W/L. Differences were also found between Asians and Caucasian subjects in MCI's W, L, and W/L.

CONCLUSIONS

The results of this meta-analysis suggest that symmetry of left and right sides and measuring method do not influence MCI dimension. Gender and ethnicity are found as influence factors for MCI dimension. We believe these findings can be helpful for dentists to decide and design the dimensions of the restorations for maxillary anterior teeth in clinical practices.

CLINICAL SIGNIFICANCE

In the process of designing maxillary anterior teeth for implantation, the contralateral MCI can be helpful to create a symmetrical esthetic restoration. For patients with maxillary anterior tooth loss or diastemas, dentists should divide the left and right space equally and keep the MCI contact area aligned with the midline. Dentists should take face size and gender into consideration when making treatment plans for the MCI. Facial parameters as well as the size ratios of the previous teeth can be evaluated and may influence the size and shape of the teeth. When measuring anterior teeth or facial dimensions for esthetic evaluation, the recommended method is to measure the perceived sizes of a facial view image created by a digital camera. Slight discrepancies may exist between the actual and measured values due to the curvature of the arch and the angle in which the photograph was taken.

Dentoskeletal and tooth-size differences between Syrian and Hungarian adolescents with Class II division 1 malocclusion: a retrospective study

Objectives

Malocclusion features differ across various populations and ethnicities. At this time, no data are available regarding the dentofacial differences between Syrian and European adolescents with Class II division 1 malocclusion, which is one of the most frequently treated pathologies in orthodontic practice. The present combined cephalometric and tooth-size study aimed to compare the dentoskeletal and tooth-size characteristics of Syrian and Hungarian adolescents with Class II division 1 malocclusion.

Results

Class II division 1 malocclusion in Hungarian adolescents was a sagittal discrepancy, while in Syrian adolescents, it was a result of excessive vertical development. Syrian adolescents had a significantly excessive vertical development when compared with Hungarian adolescents, regardless of sex (p < 0.01). Hungarian boys had significantly more protruded maxillae (p < 0.001) and less retruded mandibles (p < 0.01) when compared with Syrian boys, while Hungarian girls had significantly shorter mandibles relative to those of Syrian girls (p < 0.01). Syrian girls had significantly more protrusive lower incisors (p < 0.001), accompanied by significantly larger anterior tooth-size ratios when compared to Hungarian girls (p < 0.001). In conclusion, these findings underscore the importance of considering ethnic differences during orthodontic diagnosis and may have implications for optimizing orthodontic treatments in Syrian and Hungarian adolescents with Class II division 1 malocclusion.

A systematic review and meta-analysis on Bolton's ratios: Normal occlusion and malocclusion

INTRODUCTION

The purpose of this study was to seek and summarise the Bolton overall index (OI) and anterior index (AI) regarding normal occlusion and Angle's malocclusion according to gender, and to assess if these indices support Bolton's standards as general references.

METHODS

PubMed, LILACS, Embase, CENTRAL and Google Scholar databases were searched up to June 2019 (CRD42018088438). Non-randomised clinical studies, published in English and assessing Bolton's OI and/or AI in normal occlusion and Angle's malocclusion groups, were included. OI and AI means, sample size and SDs were collected. The National Heart, Lung, and Blood Institute's Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies was used to assess the risk of bias. Pairwise random-effects and multilevel Bayesian network meta-analyses were used to synthesise available data.

RESULTS

Fifty-three observational studies were included (11,411 participants; 3746 men, 4430 women; 15 studies lacked gender information). For normal occlusion, pooled estimates for OI and AI means were 91.78% (95% confidence interval [CI] = 91.42-92.14; I² = 92.87%) and 78.25% (95% CI = 77.87-78.62; I² = 90.67%), respectively. We could identify in Angle's Class III patients meaningful OI and AI mean deviations from normal occlusion (0.76, 95% credible interval [CrI] = 0.55-0.98 and 0.61, 95% CrI = 0.35-0.87, respectively), while in Class II patients we found a meaningful mean deviation from normal occlusion only for OI (-0.28, 95% CrI = -0.52--0.05). Concerning gender impact, male patients presented higher OI (0.30, 95% CI = 0.00-0.59) and AI (0.41, 95% CI = 0.00-0.83) mean values than female patients in Class I.

CONCLUSION

Normal occlusion OI and AI mean values differ from Bolton's original values. Class II division 2, for OI mean values, and Class III, for both OI and AI, are proportionally larger than normal occlusion patients. Gender had almost no impact on teeth mesiodistal proportion.

Elements of morphology: Standard terminology for the teeth and classifying genetic dental disorders

Dental anomalies occur frequently in a number of genetic disorders and act as major signs in diagnosing these disorders. We present definitions of the most common dental signs and propose a classification usable as a diagnostic tool by dentists, clinical geneticists, and other health care providers. The definitions are part of the series Elements of Morphology and have been established after careful discussions within an international group of experienced dentists and geneticists. The classification system was elaborated in the French collaborative network "TÊTECOU" and the affiliated O-Rares reference/competence centers. The classification includes isolated and syndromic disorders with oral and dental anomalies, to which causative genes and main extraoral signs and symptoms are added. A systematic literature analysis yielded 408 entities of which a causal gene has been identified in 79%. We classified dental disorders in eight groups: dental agenesis, supernumerary teeth, dental size and/or shape, enamel, dentin, dental eruption, periodontal and gingival, and tumor-like anomalies. We aim the classification to act as a shared reference for clinical and epidemiological studies. We welcome critical evaluations of the definitions and classification and will regularly update the classification for newly recognized conditions.

Overall and Anterior Tooth Size Ratios in a Group of Emiratis

Objectives:

The aims of this investigation in a group of Emiratis were (1) To study overall and anterior tooth size ratios in Class I normal occlusion, (2) To estimate overall and anterior tooth size ratios in different malocclusion groups, (3) To compare overall and anterior tooth size ratios in Class I normal occlusion with the Bolton standards, and (4) To determine the distribution of overall and anterior tooth size ratios ± 2 SD from Bolton mean values in all occlusion groups.

Materials and Methods:

In this cross-sectional investigation, consecutive patients’ files, including dental casts, were selected from the archives of orthodontic clinics of the Dubai Health Authority. The final sample was formed following the application of specific inclusion criteria. The sample consisted of 521 pairs of dental casts representing both sexes (males: 188; females: 333) and different malocclusion groups (Class I: 288; Class II: 110; Class III: 30) and Class I normal occlusion (93). The mean age of patients was 16.18y for Class I, 15.73y for Class II, 15.83y for Class III, and 16.55y for Class I normal occlusion. The dental casts were scanned and digitized by the first author using the Ortho Insight 3D laser scanner. Measurements were made regarding maxillary and mandibular sums of mesiodistal tooth dimension of the overall (6-6) and anterior (3-3) groups of teeth. Statistical analysis included descriptive statistics, paired t-test and Analysis of Variance (ANOVA). The level of significance was set at p<0.05.

Results:

There were statistically significant differences among malocclusion groups with regard to overall and anterior tooth size ratios. However, the comparison between the Class I normal occlusion group and the Bolton standards showed no statistically significant differences. Only five cases in Class II malocclusion presented an anterior tooth size discrepancy outside plus 2 SD from Bolton mean values and one case in Class I malocclusion presented with an overall tooth size discrepancy outside plus 2 SD from Bolton mean values.

Conclusion:

This study of the different occlusion groups of the Emirati sample concluded that (a) Class I normal occlusion cases presented similar overall and anterior tooth size ratios to Bolton standards; (b) Overall and anterior tooth size ratios among different malocclusion groups exhibited statistically significant differences; (c) Five cases in Class II malocclusion presented an anterior tooth size discrepancy outside plus 2 SD from Bolton mean values, and (d) One case in Class I malocclusion presented an overall tooth size discrepancy outside plus 2 SD from Bolton mean values.

Frequency of missing teeth and reduction of mesiodistal tooth width in Japanese patients with tooth agenesis

Background

Tooth agenesis can involve one or more congenitally missing teeth (CMT) and is the most common congenital dental anomalies in humans. Tooth agenesis and reduction of mesiodistal tooth width are reportedly associated, suggesting that the pathogenesis of the two conditions is related. The current study analyzed the frequency of tooth agenesis and mesiodistal tooth width in cases of hypodontia (1–5 CMT) and oligodontia (≥ 6 CMT) in Japanese patients based on the hypothesis that reductions in mesiodistal tooth width are more frequently associated with oligodontia than hypodontia.

Methods

Japanese patients with tooth agenesis were divided into hypodontia cases (60 female and 25 male, mean age 19.6 years, mean CMT number 1.31 ± 1.65) and oligodontia cases (26 female and 25 male, mean age 14.6 years, mean CMT number 8.07 ± 2.39). Controls included patients with a skeletal class I relationship and no CMT (female and 60 male, mean age 20.8 years). Dental casts and orthopantomograms were used to analyze the CMT frequency and mesiodistal tooth width for each group. The Kruskal-Wallis test, the Mann-Whitney U test, and Spearman’s rank correlation were used for statistical analysis.

Results

In the hypodontia group, mandibular second premolars were the most frequently missing tooth type (25.9%), followed by mandibular and maxillary lateral incisors (19.4 and 17.1%, respectively). In the oligodontia group, mandibular second premolars were the most frequently missing tooth type (88.2%), followed by maxillary second premolars (87.3%) and first premolars (63.7%). In female subjects in the hypodontia group, only maxillary lateral incisors and mandibular first molars were significantly smaller than those of the female control subjects. In contrast, in the oligodontia group, more tooth types were significantly smaller than those of the control, for both sexes. Except for maxillary second premolars in female subjects, correlations were apparent for all tooth types in both sexes.

Conclusions

Compared to hypodontia, more tooth types exhibited reduced mesiodistal tooth width in oligodontia. Correlations between CMT number and mesiodistal tooth width support the hypothesis that reduction of mesiodistal tooth width are more frequently observed in Japanese oligodontia patients than in Japanese hypodontia patients.

A Comparative Analysis of Tooth Size Discrepancy between Male and Female Subjects Presenting with a Class I Malocclusion

OBJECTIVES

To evaluate the tooth size discrepancy and Bolton's ratios between male and female subjects with a Class I malocclusion.

MATERIALS AND METHODS

The digital e-models of 100 male and 100 female 12-year-old southern Chinese children with a Class I malocclusion were selected. The mesiodistal widths from permanent first molar to the contralateral side first molar of the upper and lower dentitions were measured. Differences between the tooth size discrepancy, together with the anterior and overall Bolton's ratios between male and female subjects, were assessed using a two-sample t-test. A paired t-test was used to determine differences between antimetric pairs of teeth within the same arch.

RESULTS

Females had statistically significant smaller teeth than males (P < 0.05) except the upper left and lower left lateral incisor and lower left and right central incisors. The mean values of anterior Bolton's ratios for males and females were 77.04 and 77.03, respectively (P > 0.05), while the mean values of overall Bolton's ratios of male and female are 90.48 and 90.65, respectively (P < 0.05). The clinical significant differences (Cohen's d > 0.2) for contralateral tooth size were shown on the maxillary canines, lateral incisors, and central incisors of males; and mandibular canines and lateral incisors of females.

CONCLUSIONS

Southern Chinese females presenting with Class I malocclusions have smaller mesiodistal tooth dimensions compared to males. Both males and females presented several tooth size asymmetries. There are no statistical differences in anterior and overall Bolton's ratios between the genders.

Bolton’s Tooth Size Discrepancy in Malaysian Orthodontic Patients: Are Occlusal Characteristics Such as Overjet, Overbite, Midline, and Crowding Related to Tooth Size Discrepancy in Specific Malocclusions and Ethnicities?

Introduction

Tooth size, occlusal traits, and ethnicity are closely interrelated, and their impact on desirable orthodontic treatment outcome cannot be underestimated. This study was undertaken to assess the occlusal characteristics and ethnic variations in occlusion of Malaysian orthodontic patients and evaluate their correlation with Bolton’s tooth size discrepancy.

Materials and Methods

On 112 pretreatment study models of orthodontic patients, molar relationship, overjet, overbite, spacing, crowding, midline shift, and Bolton’s ratios were assessed. ANOVA, one-sample t-test, Chi-squared test, and Spearman’s rho correlation coefficient were used for statistical analysis.

Results

Significant difference between anterior ratio of our study and Bolton’s ideal values was found, for the entire study sample and Chinese ethnic group. Differences between races and malocclusion groups were not statistically significant (P > 0.05). Significant correlations were found as follows – in Angle’s Class I malocclusion between 1) anterior ratio and overbite, 2) overall ratio and maxillary crowding and spacing; in Angle’s Class II malocclusion between 1) anterior ratio and overjet and midline shift, 2) overall ratio and mandibular crowding; in Angle’s Class III malocclusion between 1) anterior ratio and mandibular crowding and both maxillary and mandibular spacing 2) overall ratio and mandibular crowding.

Conclusions

Significant differences in anterior ratio and Bolton’s ideal values for the Malaysian population were found, indicating variations in anterior tooth size as compared to Caucasians. Statistically significant correlations existed between Bolton’s ratios and occlusal traits. These findings can be applied clinically in diagnosis and treatment planning by keeping in mind the specific discrepancies that can occur in certain malocclusions and addressing them accordingly.

The Crown Size and Sexual Dimorphism of Permanent Teeth in Jordanian Cleft Lip and Palate Patients

Objective:

To provide a detailed description of crown size dimensions in the permanent dentition of Jordanian cleft lip and palate patients and to compare the findings with those of other populations.

Method:

The mesiodistal crown diameters of the permanent teeth of 47 patients with unilateral cleft lip and palate (UCLP), 25 patients with bilateral cleft lip and palate (BCLP), and 74 controls were measured.

Results:

The cleft group (UCLP and BCLP patients) generally demonstrated a smaller tooth size for both the maxillary and mandibular arches than did the control group. A sexual dimorphism pattern with males having larger teeth than females was observed for controls and UCLP patients. More males with BCLP had smaller teeth than did females. In the maxilla, the UCLP cleft-side teeth showed the largest percentage (4%) of sexual dimorphism, whereas the BCLP teeth achieved the highest percentage (3.4%) in the mandible. The UCLP cleft-side maxillary lateral incisors (13.2%) and BCLP mandibular canines (6%) displayed greater sexual dimorphism in crown size than did any other tooth class.

Conclusions:

Tooth size reduction occurred across all permanent tooth types and among early and late-forming teeth in cleft patients compared with the controls. This reduction was more pronounced in the maxillary incisor field. Males with UCLP and control males had larger teeth than did females, whereas a reversal of the normal dimorphism pattern was observed in patients with BCLP.

Analysis of the golden proportion and width/height ratios of maxillary anterior teeth in Arab and Kurdish populations

STATEMENT OF PROBLEM

Dentists providing anterior restorations are guided by the principles of anatomic tooth dimension. Dental biometrics should consider ethnicity to produce a more comprehensive evaluation.

PURPOSE

The purpose of this clinical study was to analyze the anatomic crowns of maxillary central incisors (CI), lateral incisors (LI), and canines (C) with respect to the golden proportion (GP) and width/height (W/H) ratio in Kurdish and Arab populations.

MATERIAL AND METHODS

Maxillary gypsum casts were obtained from 100 participants (50 from a Kurdish and 50 from an Arab population). Standardized digital photographs of each cast were recorded. The apparent and actual anterior tooth dimensions were determined by ImageJ software for the calculation of the GP and W/H ratio. Data were statistically analyzed using ANOVA to investigate ethnic, sex, and arch side differences. The chi-square test was used to explore the GP, and the 1-sample t test was used to test the ideal W/H ratio (α=.05).

RESULTS

The GP was found in both the Kurdish and Arab groups in the LI/CI mean (0.62, 0.63), but not in the C/LI mean (0.69, 0.73). No difference due to sex was detected in the LI/CI in either ethnic group, but Kurdish men had significantly larger C/LI than women (0.73, 0.66, P=.006) and larger right-side LI/CI than left (0.63, 0.60, P=.049). The W/H ratio was higher than the predicted ideal ratio of 80% (range, 88% to 90%). The LI W/H ratio in Arabs was significantly larger than in Kurds (90.3% versus 82.7%, respectively; P<.001).

CONCLUSIONS

The GP was found to exist between the apparent widths of maxillary anterior teeth LI/CI for the both populations in both men and women but not for C/LI. No ideal ratio was detected for the W/H ratios. Specific population characteristics must be taken into consideration, especially when applying the proportions to Kurdish individuals.

Applicability of Tanaka Jhonston Method and Prediction of Mesiodistal Width of Canines and Premolars in Children

INTRODUCTION

Essential part of diagnostic procedures in mixed dentition analysis is to determine adequate space available for the erupting permanent teeth. Various methods of analysis for mixed dentition are available; among them Tanaka Johnston method of space analysis for children was developed for North American children and is widely used. Its reliability among different racial and ethnic groups is yet to be determined.

AIM

To check the applicability of Tanaka Jhonston method and to derive the mesiodistal width of unerupted canines and premolars and also derive new regression equations for Bangalore population.

MATERIALS AND METHODS

Considering the selection criteria, 400 subjects of Bangalore aged 13-16 years were randomly selected and study models were prepared. Mesiodistal widths of permanent lower incisors, canines and premolars were measured. Estimated width of upper, lower canines and premolars were also derived using Tanaka Jhonston method. Data was utilized to predict mesiodistal widths of erupting permanent canines and premolars. Descriptive analysis, independent student t-test, correlation and regression analysis were carried out.

RESULTS

Measured and estimated widths of upper and lower canines and premolars were compared and the results showed that estimated widths of upper and lower canines and premolars over estimated as to the actual measurements. A new regression equation was developed by using the formula Y=a+b(X) where Y= predicted width of canine and premolars, "a" and "b" are the constants and X= lower incisal width. Regression equations for males and females were derived separately.

CONCLUSION

The original Tanaka Jhonston method over estimated for local Bangalore population. New regression equations and prediction tables were derived for males and females separately, which should be more conveniently used chairside by the clinician.

Implications of Vertebrate Craniodental Evo-Devo for Human Oral Health

Highly processed diets eaten by postindustrial modern human populations coincide with higher frequencies of third molar impaction, malocclusion, and temporomandibular joint disorders that affect millions of people worldwide each year. Current treatments address symptoms, not causes, because the multifactorial etiologies of these three concerns mask which factors incline certain people to malocclusion, impaction, and/or joint issues. Deep scientific curiosity about the origins of jaws and dentitions continues to yield rich insights about the developmental genetic mechanisms that underpin healthy craniodental morphogenesis and integration. Mounting evidence from evolution and development (Evo-Devo) studies suggests that function is another mechanism important to healthy craniodental integration and fit. Starting as early as weaning, softer diets and thus lower bite forces appear to relax or disrupt integration of oral tissues, alter development and growth, and catalyze impaction, malocclusion, and jaw joint disorders. How developing oral tissues respond to bite forces remains poorly understood, but biomechanical feedback seems to alter balances of local bone resorption and deposition at the tooth-bone interface as well as affect tempos and amounts of facial outgrowth. Also, behavioral changes in jaw function and parafunction contribute to degeneration and pain in joint articular cartilages and masticatory muscles. The developmental genetic contribution to craniodental misfits and disorders is undeniable but still unclear; however, at present, human diet and jaw function remain important and much more actionable clinical targets. New Evo-Devo studies are needed to explain how function interfaces with craniodental phenotypic plasticity, variation, and evolvability to yield a spectrum of healthy and mismatched dentitions and jaws.

Perception of Acceptable Range of Smiles by Specialists, General Dentists and Lay Persons and Evaluation of Different Aesthetic Paradigms

INTRODUCTION

One of the most important goals of restorative dentistry is to restore the patient's aesthetic. Smile analysis is subjective and it differs from person to person. An aesthetic smile involves a harmonious relationship between various parameters including the hard and soft tissues.

AIM

The aim of the study was to identify the acceptable range of several smiles (alone and in conjunction with the face) by specialists, general dentists as well as lay persons; and to identify the values of different criteria i.e., the Golden Proportion (GP), the Recurrent Esthetic Dental proportion (RED), Width to Height ratio (W/H ratio), the Apparent Contact Dimension (ACD), and lateral incisor position in a smile.

MATERIALS AND METHODS

Hundred photographs of 50 subjects were taken, 50 of the smile alone and 50 of the individual's frontal view of face. The photographs of the smiles and the faces were assessed for the aesthetic acceptability by 30 evaluators including 10 specialists with advanced training, 10 general dentists and 10 lay persons. Irreversible hydrocolloid impressions were made of the dentitions of all the individuals using stock trays and were poured in dental stone. Measurements were made on the facial surface of the teeth on the models and were recorded in millimeters using a sharp tipped digital vernier calliper. Data was analyzed to evaluate the presence of different parameters assessed in the smiles. Mean and standard deviation values for the percentage of only the agreeable smiles were calculated in both individual smile analysis and in conjunction with the face. The non agreeable smiles were excluded from further statistical analysis. Pearson Correlation Coefficient was calculated to compare the values obtained in all the three groups.

RESULTS

More number of smiles were considered agreeable by the general dentists when compared to the specialists and the number even increased in case of evaluation by lay persons. Greater number of smiles was found to be agreeable when they were evaluated in conjunction with the face.

CONCLUSION

Rather than assessment of individual numeric parameter that defines an ideal aesthetic smile, a smile to be aesthetic should harmonize with the composition of the face.

Bolton tooth size ratio among qatari population sample: An odontometric study

Objectives:

To establish the overall and anterior Bolton ratio among a sample of Qatari population and to investigate whether there is a difference between males and females, as well as to compare the result obtained by Bolton.

Materials and Methods:

The current study consisted of 100 orthodontic study participants (50 males and 50 females) with different malocclusions and age ranging between 15 and 20 years. An electronic digital caliper was used to measure the mesiodistal tooth width of all maxillary and mandibular permanent teeth except second and third molars. The Student's t-test was used to compare tooth-size ratios between males and females and between the results of the present study and Bolton's result.

Results:

The anterior and overall ratio in Qatari individuals were 78.6 ± 3.4 and 91.8 ± 3.1, respectively. The tooth size ratios were slightly greater in males than that in females, however, the differences were not statistically significant (P > 0.05). There were no significant differences in the overall ratio between Qatari individuals and Bolton's results (P > 0.05), whereas statistical significant differences were observed in anterior ratio (P = 0.007).

Conclusions:

Within the limitation of the limitations of the present study, definite conclusion was difficult to establish. Thus, a further study with a large sample in each malocclusion group is required.

Intermaxillary tooth size discrepancy in a Pakistani population: A stereomicroscope versus digital caliper

OBJECTIVE

Comprehensive diagnosis and treatment planning are essential in a successful orthodontic practice. The purpose of this study is to determine and compare intermaxillary tooth size discrepancy (IMTSD) using traditional digital caliper (DC) measurement on plaster dental models and stereomicroscopic digital dental models (SM).

MATERIALS AND METHODS

The samples were randomly selected from different states of Pakistan. Total 7168 variables were measured on plaster dental casts (128) and SM digital dental models (128) according to the selection criteria. For IMTSD, the 6 variable measured as for anterior tooth size (maxilla, mandibular), overall tooth size (maxilla, mandibular), Bolton's anterior ratios (BAR), and Bolton's overall ratios (BOR). The independent t-test and ANOVA were used for statistical analyses.

RESULTS

Significant sexual disparities in the sum of anterior tooth size and overall tooth size via DC and SM methods. No significant sexual disparities for BAR and BOR. No statistically significant differences were found in BAR and BOR between DC and SM. No significant differences were found on IMTSD ratio among different arch length and arch perimeters groups.

CONCLUSIONS

Norms were developed based on DC and SM for IMTSD. Sexual disparities were observed in the sum of teeth size. However, no significant differences in BAR and BOR for IMTSD between the two methods.

Maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width groups

OBJECTIVE

To investigate the maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width (intercanine, interpremolar, and intermolar) groups.

MATERIALS AND METHODS

The calculated sample size was 128 subjects. The crown width/height, arch length, arch perimeter, and arch width of the maxilla and mandible were obtained via digital calliper (Mitutoyo, Japan). A total of 4325 variables were measured. The sex differences in the crown width and height were evaluated. Analysis of variance was applied to evaluate the differences between arch length, arch perimeter, and arch width groups.

RESULTS

Males had significantly larger mean values for crown width and height than females (P ≤ 0.05) for maxillary and mandibular arches, both. There were no significant differences observed for the crown width/height ratio in various arch length, arch perimeter, and arch width (intercanine, interpremolar, and intermolar) groups (P ≤ 0.05) in maxilla and mandible, both.

CONCLUSIONS

Our results indicate sexual disparities in the crown width and height. Crown width and height has no significant relation to various arch length, arch perimeter, and arch width groups of maxilla and mandible. Thus, it may be helpful for orthodontic and prosthodontic case investigations and comprehensive management.

Determination of mesiodistal width of maxillary anterior teeth using inner canthal distance

BACKGROUND

Selection of appropriately sized maxillary anterior teeth is one of the important aspects of complete denture prosthodontics. In the past several methods have been proposed, but little consensus on an effective method for anterior teeth selection has been reached. Inner canthal distance is one of the reliable anatomic dimension that may provide a valid approach to anterior teeth selection. This study was aimed to ascertain the co-relation between inner canthal distance (ICD) and combined mesiodistal width of maxillary anterior teeth.

METHOD

This study was conducted in Army Dental Centre (R & R) Delhi Cantonment between Aug 2006 to Mar 2008. Eight hundred dentate Indian subjects of four different ethnic group; Such as Rajputs, Marathas, Sikh and Tamilian. 100 males and 100 females from each race under the age group of 18-30 years formed the subjects of study. The ICD and mesio-distal width of maxillary anteriors were measured using Digital Vernier Caliper. The Data obtained was statistically analyzed.

RESULTS

A consistent ratio of 1.61 was found between ICD and combined mesiodistal width of maxillary anteriors in all four ethnic group. The mean value showed no statistically significant difference between sex. The variation in the ratio between the ethnic groups was negligible.

CONCLUSION

The findings of the study indicated that, to select the combined mesiodistal width of maxillary anterior teeth, ICD of the required patient should be multiplied by 1.61. This ratio was consistent with all the four ethnic groups irrespective of sex.

Relationship between maxillary central incisor proportions and facial proportions

STATEMENT OF PROBLEM

No universally accepted parameter exists for selecting maxillary central incisors (MCIs) relative to facial proportions.

PURPOSE

The purpose of this prospective clinical study was to determine the relationship between MCIs and facial height and width in adults, intersex differences, and measurement differences between right and left MCI.

MATERIAL AND METHODS

A prospective study was undertaken of 149 dental students (F:76; M:73) aged between 18 and 30 years. Anthropometric MCI and horizontal and vertical facial measurements were recorded with digital calipers by 1 operator. Correlation was investigated with Pearson correlation coefficients (α=.05). Two-sample t tests were used for intersex comparisons and paired t tests to compare right and left MCIs. Intraexaminer reliability was tested by remeasuring 25 participants and applying the Bland-Altman and Lin analyses.

RESULTS

The mean MCI height was 10.28 mm (right and left) and the mean widths were 8.65 mm (right) and 8.66 mm (left). Intersex incisor differences existed for height measurements (M:F 0.54 mm [right], 0.46 mm [left]) and width measurements (M:F 0.26 mm) but not for width-to-height ratios (F=0.85; M=0.84). A mean ratio of 15.56 was found between bizygomatic width:tooth width (M=15.75, F=15.37) and of 17.93 between total face height:MCI height (M=17.97, F=17.89). Correlation coefficients were low for all tooth:face measurements. Intraexaminer reliability was clinically acceptable.

CONCLUSIONS

Men had larger teeth and faces but similar width:height ratios. There was no significant size difference between right and left MCI, little individual relationship between tooth:face proportions, and insignificant sex influence. The "biometric ratio"' of 1:16 for MCI:bizygomatic width was not reconfirmed exactly. A ratio of 1:18 is proposed for MCI height to total face height (Tr-Me') and 1:12 for face height (N'-Me').

Bolton tooth size ratio among Sudanese Population sample: A preliminary study

Background:

The study of the mesiodistal size, the morphology of teeth and dental arch may play an important role in clinical dentistry, as well as other sciences such as Forensic Dentistry and Anthropology.

Aims:

The aims of the present study were to establish tooth-size ratio in Sudanese sample with Class I normal occlusion, to compare the tooth-size ratio between the present study and Bolton's study and between genders.

Materials and Methods:

The sample consisted of dental casts of 60 subjects (30 males and 30 females). Bolton formula was used to compute the overall and anterior ratio. The correlation coefficient between the anterior ratio and overall ratio was tested, and Student's t-test was used to compare tooth-size ratios between males and females, and between the present study and Bolton's result.

Results:

The results of the overall and anterior ratio was relatively similar to the mean values reported by Bolton, and there were no statistically significant differences between the mean values of the anterior ratio and the overall ratio between males and females. The correlation coefficient was (r = 0.79).

Conclusions:

The result obtained was similar to the Caucasian race. However, the reality indicates that the Sudanese population consisted of different racial groups; therefore, the firm conclusion is difficult to draw. Since this sample is not representative for the Sudanese population, hence, a further study with a large sample collected from the different parts of the Sudan is required.

Is arch form influenced by sagittal molar relationship or Bolton tooth-size discrepancy?

Background

Orthodontic patients show high prevalence of tooth-size discrepancy. This study investigates the possible association between arch form, clinically significant tooth-size discrepancy, and sagittal molar relationship.

Methods

Pretreatment orthodontic casts of 230 Saudi patients were classified into one of three arch form types (tapered, ovoid, and square) using digitally scanned images of the mandibular arches. Bolton ratio was calculated, sagittal molar relationship was defined according to Angle classification, and correlations were analyzed using ANOVA, chi-square, and t-tests.

Results

No single arch form was significantly more common than the others. Furthermore, no association was observed between the presence of significant Bolton discrepancy and the sagittal molar relationship or arch form. Overall Bolton discrepancy is significantly more prevalent in males.

Conclusions

Arch form in a Saudi patient group is independent of gender, sagittal molar relationship, and Bolton discrepancy.

Association between tooth size and interarch relationships in children with operated complete unilateral cleft lip and palate

Background

To evaluate mesiodistal tooth width of patients with UCLP comparing tooth size in different Goslon Yardstick scores and between cleft and noncleft sides.

Methods

The Department of Orthodontics at Bauru Dental School and Hospital of Rehabilitation of Craniofacial Anomalies – University of Sao Paulo. Hundred forty-four pairs of dental casts of patients with UCLP. These dental casts were divided into 3 groups: group I (patients with Goslon rating of 1 and 2), group II (Goslon rating of 3) and group III (Goslon rating of 4 and 5). The control group consisted of 40 pairs of dental casts of noncleft Class I patients at the same age range. Mesiodistal width of maxillary permanent central incisors, lateral incisors and first molars were measured using a digital caliper. Intergroup comparisons were performed using ANOVA followed by Tukey tests. T tests were used to compare tooth size between cleft and noncleft sides (p <0.05).

Results

Differences for tooth size were observed between individuals with different Goslon Yardstik scores. Mesiodistal widths of maxillary central incisors in subjects of Group III were significantly smaller compared to Group I and to the control group. The lateral incisors at the cleft side were smaller than the antimere.

Conclusions

Mesiodistal tooth size was smaller in poor Goslon yardstick scores. Cleft and noncleft sides demonstrated similar maxillary tooth size except for the lateral incisor.

Tooth size discrepancy in a Libyan population, a cross-sectional study in schoolchildren

Objetives: The aim of this cross-sectional study was to investigate the tooth size discrepancy (TSD) in a group of Libyan schoolchildren, and to compare TSD between sexes.

MATERIAL AND METHODS

The sample comprised 333 Libyan schoolchildren (162 males with a mean (SD) age of 14.4 (1.1) years, and 171 females with a mean age of 14.1 (1.1) years). Anterior and overall TSD ratios were computed using descriptive statistics. Sex differences were statistically assessed using an independent t-test (P<0.05).

RESULTS

Males showed significantly wider MD tooth width compared to females (P<0.05), except for the maxillary first premolars and mandibular central incisors. There were significant differences (P<0.05) between the paired (right and left sides) tooth measurements except for the maxillary and mandibular central and lateral incisors as well as mandibular canines. The mean (SD) for overall and anterior TSD ratios were 91.3% (2.1) and 78.2% (2.6), respectively, with no significant sex differences for both variables (P> 0.05). The percentages of participants showing more than 2 SD variation for the anterior and overall ratios comprised 3% and 4.2% of the total sample, respectively.

CONCLUSIONS

The anterior and overall TSD ratios for the examined subjects were established and showed no significant sexual dimorphism. Key words:Tooth size discrepancy, Libyan, schoolchildren.