Age estimation in adults by canine teeth: a systematic review of the Cameriere method with meta-analysis on the reliability of the pulp/tooth area ratio

The age estimation of an adult using methods accessible to the forensic routine is a goal pursued by forensic experts. Cameriere, Ferrante and Cingolani (2004) proposed the use of the pulp/tooth area ratio of canine teeth as a promising variable, but its reliability has shown conflicting results in the scientific literature. This article aimed to carry out a systematic review with meta-analysis to verify whether the pulp/tooth area ratio of canine teeth includes a variable that can be used alone to estimate dental age in adults. A systematic search was carried out in six databases using keywords related to the theme in Portuguese, English, and Spanish. The study selection process followed pre-established eligibility criteria. Assessments were carried out regarding risk of bias and publication bias of selected studies, and meta-analysis was carried out considering Pearson's correlation coefficient between pulp/tooth area ratio and chronological age as effect measure. Most selected studies showed low risk of bias; no publication bias was found when all studies were considered, and potential publication bias was found when outliers were removed. Despite the high heterogeneity among studies and the need for more research, it could be observed that the pulp/tooth area ratio has strong negative correlation with chronological age, and the pulp/tooth area ratio could be derived from both periapical radiographs and orthopantomographs. Therefore, it is suggested that there is scientific evidence that the pulp/tooth area ratio obtained from canine teeth is reliable for dental age estimation in adults.

Statistical shape analysis of maxillary palatal morphology in patients with palatally displaced canines

OBJECTIVE

Maxillary morphology has long been a subject of interest due to its possible impact on palatally and labially displaced canines. This study aims to conduct a comparison of the palate morphology between individuals with palatal and labially displaced canines and control subjects using statistical shape analysis on a coronal cross-sectional of CBCT images.

MATERIALS AND METHODS

Patients aged between 12 and 43 years with palatally or labially displaced canines referred to Hamadan School of Dentistry between 2014 and 2019 were recruited for this retrospective study. The sample included 29 palatally displaced canines (PDC), 20 labially displaced canines (LDC), and 20 control groups (CG). Initially, the maxillary palate coronal section was acquired and landmarked in the region between the right and the left first molar. Procrustes and principal component analyses were used to identify the primary patterns of palatal shape variation. Statistical tests were then performed to examine both shape and size differences.

RESULTS

According to the results of Hotelling's T2 test, there is a significant difference between the mean shape of palate in PDC and CG (P = 0.009), while the difference between the PDC-LDC and LDC-CG groups is not significant. The longest full Procrustes distance was observed between PDC and CG (distance = 0.043), and the shortest full Procrustes distance was observed between LDC and CG (distance = 0.029). The first two principal components accounted for 84.47% of the total variance. The predictive accuracy of the discriminant analysis model showed that 72.46% of cases were correctly classified into the three study groups.

CONCLUSIONS

In terms of centroid size, there was no significant difference in the sectional area between the three groups, but the difference between the mean shape of palate in the PDC and CG groups was significant. The PDC group showed more prominent mid-palatal area in the molar region.

Three-dimensional evaluation of social smile asymmetry in patients with unilateral impacted maxillary canine: a 3D stereophotogrammetry study

OBJECTIVE

This study aimed to evaluate social smile asymmetry in patients with unilateral impacted maxillary canine on 3D stereophotogrammetric images.

MATERIAL AND METHODS

The 3D social smile images of participants with unilateral impacted maxillary canine (n:20) and without impaction as a control group (n:20) were included. The images were recorded with a hand-held 3D stereophotogrammetry device (Fuel3D® Scanify®) and Geomagic Essentials 2 reverse engineering software were used for analyses. After the orientation process of the 3D records, the tissues around the smile area were divided into five morphological regions: cheek, upper lip lateral and medial, and lower lip lateral and medial. The deviation margins in the negative and positive directions for the 95% mesh rate and the total percentages of meshes between - 0.5- and + 0.5-mm deviations were calculated. ICC, paired samples t test, independent samples t test, and the Mann-Whitney U test were used for statistical analyses.

RESULTS

In individuals with impacted canine, the amount of maximum positive deviation in the upper lip medial was 5.64 mm ± 1.46 and maximum negative deviation was - 4.6 mm ± 1.17. In the control group, mean of deviation limits for all parameters was less than 1.19 mm ± 2.62, while in individuals with unilateral impacted maxillary canine, the maximum value was 8.34 mm ± 2.23. The mesh percentage between - 0.5 and 0.5-mm deviations was over 95% in all morphological areas in the control group, while in the impacted canine group, the number of meshes within the specified deviation limits was less than 95%.

CONCLUSION

Individuals with unilateral impacted maxillary canine exhibit greater asymmetry in social smile compared to the control group, with the asymmetry being most prominent near the corners of the mouth and cheeks.

CLINICAL RELEVANCE

Amount of asymmetry was higher in impaction group compared to the control group in social smile. The quantification of a possible smile asymmetry due to the impacted canine is crucial for the diagnosis and treatment planning of orthodontic and/or orthognathic cases for ideal aesthetic results. Hence, smile asymmetry should not be overlooked and should be considered in diagnosis and treatment planning.

[Esthetic proportions of maxillary anterior tooth among 300 normal occlusion college students in Shanxi province]

Objective: To explore the relationship between the width ratios of maxillary anterior teeth, the width/height ratios of maxillary central incisor and the esthetic proportions among individual normal occlusion, and to provide reference for the esthetic design of anterior teeth. Methods: A total of 300 Shanxi Medical University students who were residents from Shanxi province with normal occlusion (110 males, 190 females, aged 18-30 years) were recruited in this study from October 2020 to March 2021. Standardized digital photographs of the maxillary anterior tooth in natural head position were obtained, the perceived width of the maxillary anterior teeth (maxillary central incisors, lateral incisors and canines) on the left and right sides and height of maxillary central incisor were measured on the standardized digital photographs, then the width ratios of adjacent maxillary anterior teeth including the lateral incisor/central incisor width ratio (LI∶CI), the canine/lateral incisor width ratio (C∶LI), and the width/height ratios (W/H ratio) of the maxillary central incisor were calculated. The independent sample t test was used to compare the sex differences of each measurement project, Single sample t test was used to compare the difference of adjacent maxillary anterior teeth width ratios with golden proportion (0.618 and 0.618), Preston proportion (0.66 and 0.84), the recurring esthetic dental (RED) proportion (0.70 and 0.70). The percentage of anterior tooth width/intercanine width was calculated, the number and proportion of teeth conforming to golden percentage (25%, 15%, 10%)±1% or modified golden percentage (22.5%, 15.0%, 12.5%)±1% were calculated. The number and proportion of width/height ratio of maxillary central incisor ranged from 0.75 to 0.85 was counted. Results: The widths of maxillary central incisor, lateral incisor and canine were (8.50±0.52), (6.23±0.53) and (5.18±0.55) mm, respectively, the corresponding tooth of male [(8.74±0.49), (6.37±0.52), (5.41±0.47) mm] was significantly higher than that of female [(8.37±0.50), (6.15±0.52), (5.04±0.54) mm] (t=6.40, 3.55, 6.23,P<0.05). The width ratio of maxillary lateral incisor/central incisor was 0.73±0.05, and there was no significant difference between genders (t=-1.06, P>0.05). The width ratio of canine/lateral incisor was 0.84±0.10, and it was significantly higher in male (0.85±0.10) than in female (0.82±0.10) (t=2.42, P<0.05). Two width ratios of maxillary anterior teeth were significantly different from golden proportion and the RED proportion (t=38.50, 35.74, 11.48, 22.20, P<0.05). The lateral incisor/central incisor was significantly different from that of Preston proportion (t=24.66, P<0.05), while the canine/lateral incisor was not significantly different from that of Preston proportion (t=-0.92, P>0.05). In this study, a total of 0% (0/600) of central incisors, 63.0% (378/600) of lateral incisors and 5.8% (35/600) of canines met the golden percentage±1%. There were 42.8% (257/600) of central incisors, 63.0% (378/600) of lateral incisors and 56.7% (340/600) of canines met the modified golden percentage±1%. The width/height ratio of maxillary central incisors was 0.86±0.08, and there was no significant difference between genders (t=-0.88, P>0.05). Only 36.3% (218/600) of the subjects in this study ranged from 0.75 to 0.85. Conclusions: Gender differences should be considered in the esthetic design of anterior teeth; for the width ratios of maxillary anterior teeth, the golden proportion, the RED proportion and golden percentage do not accord with the natural tooth morphological characteristics of Shanxi nationality college students in normal occlusion. Preston proportion and modified golden percentage are of more reference value. The width/height ratio of maxillary central incisors is different from 0.75-0.85.

Comparison of Chu's Proportion Gauge with a T-bar Tip and a Two-Tip Compass in the Determination of Anterior Dentition Tooth Size in a Group of Puerto Ricans

OBJECTIVE

Compare maxillary anterior dentition measurements, using Chu's proportion gauge with a T-bar tip (PG-TT) and a Two-Tip Compass (T-TC), in a group of Puerto Ricans, to determine the reliability of the PG-TT.

METHODS

This cross-sectional study was conducted at the University of Puerto Rico, School of Dental Medicine, Medical Sciences Campus. The participants (18-35 years old) were dental students or employees of the university. Previously, the examiner had been trained and calibrated in instrument usage. Calibration participants (n = 16) received an oral exam, prophylaxis, and a chlorhexidine mouthwash for home use. After 3 days, the upper-anterior teeth were measured using the 2 instruments. The agreement was determined using weighted kappa statistics (Kw), and 0.80 was the minimum acceptable level. The examiner achieved almost perfect agreement (inter-examiner KwT-TC = 0.95 [0.96-0.93]; KwPG-TT = 0.82 [0.81-0.87]) with a reference examiner.

RESULTS

Fifty participants (25 women and 25 men) were evaluated. Length: The teeth of the men presented an unacceptable level of agreement, except for in the right central incisors. For the women, a strong level of agreement was observed only in the lateral incisors and left canines. When the teeth of both sexes were considered, a strong level of agreement was detected, except for in the right canines and left central incisors. Width: The level of agreement was unacceptable, except for in the right canines (distal).

CONCLUSION

T-TC is a more reliable instrument to measure tooth dimensions as compared to the PG-TT.

Sexual dimorphism of the enamel and dentine dimensions of the permanent canines of the Middle Pleistocene hominins from Sima de los Huesos (Burgos, Spain)

Sexual dimorphism is an important component of the total variation seen in populations and plays a key role in taxonomic debates. In this study, microtomographic (microcomputed tomography) techniques were applied to a sample of hominin teeth from the Sima de los Huesos site (Spain). Dental tissue proportions of the permanent canines were assessed to characterize the pattern and degree of sexual dimorphism within this population. In addition, the possible similarities and differences with the Homo neanderthalensis remains from Krapina (Croatia) and with a recent modern human sample were evaluated. A combination of classical statistical approaches with more novel techniques allowed us not only to ratify the sex allocation of the individuals previously assigned in the literature but also to estimate the sex of the youngest individuals, which were not assessed in previous studies. Likewise, the sexes of certain extensively worn canines and isolated pieces were estimated. As a result, the sex ratio observed in our dental sample from the Sima de los Huesos population is 5:9 (N_m:N_f). In general terms, both Sima de los Huesos and Krapina dental samples have a degree of sexual dimorphism in their permanent canine tissue proportions that does not surpass that of modern humans. The marked dimorphic root volume of Sima de los Huesos mandibular canines is the exception, which surpasses the modern human mean, although it falls within the 95% confidence interval. Therefore, our results do not support that dental tissue proportions of the European Middle Pleistocene populations were more dimorphic than in modern humans. However, the differences in canine tissue proportions are great enough to allow sex estimation with a high degree of confidence.

Prediction of maxillary canine impaction based on panoramic radiographs

OBJECTIVES

The objective of this article is to establish a large sample-based prediction model for maxillary canine impaction based on linear and angular measurements on panoramic radiographs and to validate this model.

MATERIALS AND METHODS

All patients with at least two panoramic radiographs taken between the ages of 7 and 14 years with an interval of minimum 1 year and maximum 3 years (T1 and T2) were selected from the Department of Oral Health Sciences, University Hospital Leuven database. Linear and angular measurements were performed at T1. From 2361 records, 572 patients with unilateral or bilateral canine impaction were selected at T1. Of those, 306 patients were still untreated at T2 and were used as study sample. To construct the prediction model, logistic regression analysis was used.

RESULTS

The parameters analyzed through backward selection procedure were canine to midline angle, canine to first premolar angle, canine cusp to midline distance, canine cusp to maxillary plane distance, sector, quadratic trends for continuous predictors, and all pairwise interactions. The final model was applied to calculate the likelihood of impaction and yielded an area under the curve equal to 0.783 (95% CI [0.742-0.823]). The cut-off point was fixed on 0.342 with a sensitivity of 0.800 and a specificity of 0.598. The cross-validated area under the curve was equal to 0.750 (95% CI [0.700, 0.799]).

CONCLUSION

The prediction model based on the above mentioned parameters measured on panoramic radiographs is a valuable tool to decide between early intervention and regular follow-up of impacted canines.

Sex Predictability by Using Mandibular Canine Index

BACKGROUND

Canines are known for their higher resistance to trauma and pathological alterations when compared to other teeth. Among all the teeth, canines show highest sexual dimorphism.

METHODS

This descriptive cross-sectional study was commenced from January 2019 to April 2019 after the ethical approval from Institutional Review Committee. The maximum mesio-distal widths of right and left mandibular canines and mandibular inter-canine arch width were measured on the cast with the help of a divider and digital vernier callipers. Mandibular canine index was calculated by dividing the mesio-distal width of each mandibular canine with inter-canine arch width. Data was entered and analyzed using Statistical Package for the Social Sciences version 21.

RESULTS

Sex predictability by using mandibular canine index in the present study showed poor sex predictability (57.5% - 62.5%).

CONCLUSIONS

Sex determination should be done by other methods and mandibular canine index should be used cautiously in Nepalese population.

Orthopantomographic analysis of the intraosseus position of the maxillary canines

The aim of this work was to analyse the intraosseous position of the maxillary canine in orthodontic patients. It was an exploratory pilot study prior to the next research work to develop a predictive model based on a regression analysis initially including a large number of variables. 105 subjects from 6 to 12 years from both genders were included in this study. Four variables were used. The study showed that there was no marked gender dimorphism concerning the intrabony position of the canine; the latter is quite similar on both sides, and the older the age, the smaller the angulation of the canine. The values obtained for the angulation of the canine, its depth of impaction, its position in relation to the lateral incisor and the premolars, correspond to an average impaction severity and treatment difficulties.

Sexual ornaments but not weapons trade off against testes size in primates

Males must partition their limited reproductive investments between traits that promote access to females (sexual ornaments and weapons) and traits that enhance fertilization success, such as testes and ejaculates. Recent studies show that if the most weaponized males can monopolize access to females through contest competition, thereby reducing the risk of sperm competition, they tend to invest less in sperm production. However, how males invest in sexual ornaments relative to sperm production remains less clear. If male ornaments serve as badges of status, with high-ranking males attaining near-exclusive access to females, similar to monopolizing females through combat, their expression should also covary negatively with investment in post-mating traits. In a comparative study across primates, which exhibit considerable diversification in sexual ornamentation, male weaponry and testes size, we found relative testes size to decrease with sexual ornaments but increase with canine size. These contrasting evolutionary trajectories might be driven by differential selection, functional constraints or temporal patterns of metabolic investment between the different types of sexual traits. Importantly, however, our results indicate that the theory of relative investments between weapons and testes in the context of monopolizing females can extend to male ornaments.

Three-dimensional evaluations of the digital casts of morphologic maxillary teeth symmetry in patients with unilateral palatally displaced canines

INTRODUCTION

The goal of this study was to compare the size and morphologic symmetry of the maxillary teeth in subjects with and without unilateral palatally displaced canines (PDCs).

METHODS

Plaster casts of 38 subjects (mean age 14.75 ± 0.95 y) with unilateral PDCs were selected (study group [SG]) and compared with casts from an age- and sex-matched control group (CG). Then dental casts of both groups were scanned into 3-dimensional (3D) models. Tooth sizes (mesiodistal [MD] and buccolingual [BL] widths and volumes) for SG and CG were measured. Afterward, 3D deviation analysis was carried out with the use of Geomagic Control X software. All of the data were normally distributed according to parametric tests.

RESULTS

All of the maxillary tooth diameters were smaller in SG than in CG. Statistically significant differences (P ≤ 0.001) were obtained when comparing the widths and volumes of the PDC quadrant and the unaffected quadrant of the same patient. Morphologic tooth symmetry by surface-to-surface matching for SG (PDC side vs non-PDC side) and CG (right vs left quadrant) demonstrated significant (P ≤ 0.001) but small differences, except for the lateral upper incisors (71.27%).

CONCLUSIONS

Unlike control subjects, PDC patients showed high mismatching of lateral incisor crowns of ∼30%.

Morphology of maxilla in patients with palatally displaced canines

OBJECTIVES

The aim of this study was to investigate the possible relationship between the morphology of maxilla and the palatally displaced canines (PDC).

MATERIALS AND METHODS

In this cross-sectional study, there were 101 patients (45 males, 56 females) aged 12 to 16years, referred to Hamadan school of dentistry in 2014. They were divided into 3 groups: the bilateral PDC (PDCb) group (male=15, female=21), the unilateral PDC (PDCu) group (male=16, female=19), and the control group (male=14, female=16). Five morphology related variables including intermolar width, maxillary arch length, palatal vault depth, palatal intermolar area, and nasal width were measured using CBCT images with Dolphin Imaging software, version 11.5. Statistical analysis was performed with ANOVA and the Dunnett test using SPSS software, version 16.0.

RESULTS

Only the palatal intermolar area and the palatal vault depth values were significantly less in the PDCu and the PDCb groups than those in the control group (the palatal intermolar area: 376.17, 381.93, and 423.75mm², the palatal vault depth: 13.19, 13.42, and 14.59mm; respectively; P<0.05). For all the variables, there was no statistically significant difference between the PDCu and PDCb groups.

CONCLUSION

Decreased palatal vault depth and palatal intermolar area may be correlated with greater chance of palatal displacement of canines. Future prospective studies in mixed dentition patients are needed as a predictive factor to find the probability of PDC.

New regression equations for mixed dentition space analysis in Nepalese mongoloids

BACKGROUND

Mixed dentition space analysis methods using regression equations, namely, Moyers' analysis and Tanaka-Johnston analysis are commonly used around the world. However, the applicability of these analyses among different racial groups have been questioned. The primary objective of this study was to assess the applicability of the Moyers' and Tanaka-Johnston analyses among Nepalese Mongoloids and to develop regression equations for the same population if needed.

METHODS

One hundred (50 males and 50 females) pre-treatment study models of the Nepalese Mongoloid patients undergoing orthodontic treatment were retrieved from the archives of the department of Orthodontics. The mesiodistal widths of mandibular incisors and widths of canines and premolars of all 4 quadrants were measured by a single investigator using a digital caliper to the nearest 0.01 mm. Predicted widths of canines and premolars were obtained using standard Moyers' and Tanaka-Johnston analyses and then compared with the measured widths.

RESULTS

The measured widths of canines and premolars were significantly different from the predicted widths obtained from Moyers' and Tanaka-Johnston analyses. Strong and positive correlations were found between the sum of mesiodistal widths of mandibular incisors and the sum of mesiodistal widths of canines and premolars in males (0.73 for maxillary arch and 0.68 for mandibular arch) and females (0.64 for maxillary arch and 0.79 for mandibular arch).

CONCLUSIONS

The Moyers' and Tanaka-Johnston analyses did not accurately predict the mesiodistal width of unerupted canines and premolars for Nepalese Mongoloid population. Hence, new regression equations have been developed for this population. However, validation studies should be conducted to confirm the applicability and accuracy of these equations.

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.

[Esthetic evaluation of frontal smile on different crown heights of lateral incisor and canine]

To investigate the effect of different crown heights of lateral incisor and canine on smile esthetics perception between orthodontists and patients.
 Methods: A total of 31 orthodontists and 56 patients on smile aesthetics perception were investigated. We adjusted the height of lateral incisor and canine to get 20 kinds of anterior tooth area morphology by Photoshop and asked interviewees to grade. Scores of satisfaction were recorded by Likert method.
 Results: Subjects in the 2 groups preferred smiles with upper anterior teeth edge parallel to lower lip. There was better acceptance for longer canines and less satisfaction at shorter lateral incisors in patients. Patients also got higher discrete degree of evaluation results and more rigorous about smile esthetics than orthodontists.
 Conclusion: Orthodontists and patients have different satisfaction at esthetics of anterior teeth. Esthetics preference should be considered in orthodontic treatment schedule.

Canine and Premolar Root Dimensions in Chinese. A Reference for Osteoodontokeratoprosthesis Surgery

PURPOSE

Osteoodontokeratoprosthesis (OOKP) surgery is used to restore vision in end-stage corneal disorders, where an autogenous tooth supporting an optical cylinder is implanted through the cornea under a buccal mucosal graft. The ideal tooth for OOKP is a healthy single-rooted permanent tooth with sufficient buccolingual/palatal root diameter to accommodate an optical cylinder. The aim of this study was to determine the buccolingual/palatal diameters of canine and premolar roots in Chinese, for selection of teeth for OOKP surgery.

DESIGN

This was an anatomical study on root dimensions of extracted intact teeth.

METHODS

Extracted canine and premolar teeth (excluding maxillary first premolars) were collected and the buccolingual/palatal and mesiodistal diameters of the root at the cervical line and at 2-mm intervals below the cervical line were measured with Vernier calipers. Other measurements included total tooth length, crown buccolingual/palatal diameter, and root length. Mean and minimum buccolingual/palatal root diameters were compiled for each 2-mm interval.

RESULTS

A total of 415 extracted teeth (198 male, 217 female) were collected and measured. Recorded dimensions of keratoprostheses in 55 previous OOKP surgeries were used to establish acceptable lamina dimensions to ascertain root size adequacy. Premolars in Chinese female patients were undersized in a small minority. Minimal dimensions of teeth were insufficient if at 6 mm root level, the buccolingual/palatal width was less than 5 mm, or the mesiodistal width was less than 3 mm. This was noted in female mandibular first premolars (5.6%), maxillary second premolars (4.5%), and mandibular second premolars (1.5%).

CONCLUSIONS

Canines have adequate dimensions for OOKP surgery. However, premolars in Chinese females may be undersized in a small minority.

Details of pleasing smiles

PURPOSE

To determine the most and least attractive smiles from a Brazilian sample and to correlate the anatomical characteristics identified in these smiles.

MATERIALS AND METHODS

Orthodontists, dentists, and laypeople assessed the photographs of 86 students (66 women and 20 men), aged between 19 and 30 years, using a visual analog scale (VAS). An evaluator blinded to the results measured the esthetic composition of the eight photographs with the highest and the eight with the lowest ratings for women, and the two with the highest and the two with the lowest ratings for men. The mean and standard deviations were calculated for the descriptive analysis.

RESULTS

A total of 42 anatomical smile details were identified and described, obtaining the means of the characteristics.

CONCLUSIONS

The following characteristics were observed from the selected most attractive smiles: parallel smile arc, oval-shaped incisors with square-rounded edges, increase of the incisal embrasure and reduction of connector space in distal progression, display of maxillary incisors and minimum display of mandibular teeth, gingival margin of central incisors 0.5 mm coronal to the canines and 0.8 mm apical to the lateral incisors, posterior gingival display of 1.5 mm, less than 20% of buccal corridor and display of 12 teeth, and canines with -2 degrees of inclination. The most attractive smiles also had an absence of asymmetries, diastemas, black spaces, incisal plane inclination, and anterior gingival display.

The dental phenotype of hairless dogs with FOXI3 haploinsufficiency

Hairless dog breeds show a form of ectodermal dysplasia characterised by a lack of hair and abnormal tooth morphology. This has been attributed to a semi-dominant 7-base-pair duplication in the first exon of the forkhead box I3 gene (FOXI3) shared by all three breeds. Here, we identified this FOXI3 variant in a historical museum sample of pedigreed hairless dog skulls by using ancient DNA extraction and present the associated dental phenotype. Unlike in the coated wild type dogs, the hairless dogs were characterised in both the mandibular and maxillary dentition by a loss of the permanent canines, premolars and to some extent incisors. In addition, the deciduous fourth premolars and permanent first and second molars consistently lacked the distal and lingual cusps; this resulted in only a single enlarged cusp in the basin-like heel (talonid in lower molars, talon in upper molars). This molar phenotype is also found among several living and fossil carnivorans and the extinct order Creodonta in which it is associated with hypercarnivory. We therefore suggest that FOXI3 may generally be involved in dental (cusp) development within and across mammalian lineages including the hominids which are known to exhibit marked variability in the presence of lingual cusps.

Maxillary canine morphology: comparative and descriptive analysis from periapical radiographs and cone beam computed tomography

The anatomical characteristics of permanent maxillary canines were evaluated through visual examination, periapical radiography, and cone beam computed tomography (CBCT), and measurements obtained from the images and directly on the teeth were compared. Fifty extracted human maxillary canines were classified according to the side of the mouth. The direction of root curvature and location of the apical foramen were also verified. Periapical radiographs and CBCTs of the specimens were obtained. The number of root canals was verified. Tooth length and the mesiodistal and buccopalatal widths of the root were measured directly on the specimens as well as on the radiographs and CBCTs. Data were analyzed by chi-square testing and analysis of variance (α = 0.05). All teeth-26 (52%) from the right side of the dental arch and 24 (48%) from the left-had only 1 main canal each. The apical foramen was located exactly in the root apex in 34 teeth (68%). Root curvature toward the distal side was observed in the apical third in 23 teeth (46%). There were no statistically significant differences between the canines' arch side and either the foramen location (P = 0.104) or the root curvature (P = 0.215). No statistically significant differences were found in measurements of tooth length (P = 0.669), mesiodistal root width (P = 0.517), or buccopalatal root width (P = 0.672) obtained from specimens and images. Both CBCTs and periapical radiographs were reliable for determining the tooth length, mesiodistal root width, and buccopalatal root width of maxillary canines and produced statistically similar measurements.

Morphological relationship analysis of impacted maxillary canines and the adjacent teeth on 3-dimensional reconstructed CT images

OBJECTIVE

To examine whether there is a relationship between maxillary canine impaction and the morphologic characteristics of the maxillary dentition, especially the root of the lateral incisor.

MATERIALS AND METHODS

In this study, we selected only patients with unilateral maxillary canine impaction to compare the morphologic characteristics of the dentition on the impaction side and the clinically normal eruption side. The sample size was decided to be 40 based on the pilot study. To minimize bias depending on sex and location of the maxillary canine impaction, we selected equal numbers (20) of boys and girls, and equal cases (20) of buccal impaction and palatal impaction. Under the aforementioned conditions, the mean age was 13.5 ± 2.3 years. The multislice spiral computed tomography images of these 40 subjects were converted into three-dimensional (3D) reconstructed images using the OnDemand 3D program (Cybermed Co, Seoul, Korea). Then we measured the morphologic characteristics of the individual teeth on the obtained 3D teeth images.

RESULTS

Length and volume of the maxillary lateral incisor's roots were significantly smaller on the impaction side compared with the normal eruption side (P = 0.001 and P = 0.006, respectively). The width and volume of the canine's crown were significantly greater on the impaction side compared with the normal eruption side (P = 0.020 and P < .0001, respectively).

CONCLUSION

These results might help to prove the hypothesis that the smaller-sized lateral incisor roots and greater-sized canine crowns are the influential etiologic factors in maxillary canine impaction.

Accuracy and evaluation of a new regression equation in predicting the width of unerupted permanent canines and premolar teeth

AIM

To assess the applicability of two regression equations based on mixed dentition analysis and to propose and evaluate a new regression equation using the mandibular incisors and first permanent molars as predictors in calculating the size of unerupted permanent canines and premolar teeth in school children.

METHODS

Dental study casts of 100 children (50 males and 50 females) aged 11-14 years from schools situated in Moradabad, Uttar Pradesh, India were used. The analysis of Tanaka Johnston, Bernabe Flores-Mir and the proposed equation were tested on the casts.

RESULTS

The analysis of Tanaka Johnston and Bernabe Flores-Mir tended to overestimate the mesio-distal width of the canines and premolars. The proposed equation also overestimated but the mean difference showed a closer approximation with the actual measured values compared to the other two equations.

CONCLUSION

Validating studies with a similar population must be conducted to confirm the applicability and precision of the proposed equation.

Assessment of the Pubertal Growth Period using the Open Apices of the Lower Teeth

AIM

The purpose of this study was to evaluate whether the open apex measurements of the lower teeth can be used for prediction of the pubertal growth spurt.

MATERIALS AND METHODS

The study group consisted of 150 males and 142 females ranging in age from 10 to 16 years. A total of 292 panoramic and 292 hand-wrist radiographs were obtained and analyzed. The skeletal maturity was determined according to the skeletal maturity indicators (SMIs) developed by Fishman. The open apices measurements of the left lower teeth were made according to the method described by Cameriere.

RESULTS

The Spearman rank order correlation coefficient revealed a relationship between the skeletal maturity stages and the open apex measurements. These correlations ranged from 0.577 for the lower second premolar to 0.830 for the lower canine. The measurement of the left lower canine showed the highest correlation, so its relationship with the SMIs was further investigated. The measurements of 6.07 (or greater) indicated to SMI4, and 2.485 (or lesser) indicated to SMI7.

CONCLUSION

The skeletal maturity well related to the measurements of the open apices of the lower teeth. Lower canine open apex measurements could be used as an indicator of the SMI4 and SMI7.

CLINICAL SIGNIFICANCE

The measurements of the open apices of the left lower canines from panoramic radiographs may be clinically useful as an indicator of the beginning and the ending of the pubertal growth period.

Computer-tomographic characteristics of root length incisors and canines of the upper and lower jaws in boys and girls with different craniotypes and physiological bite

INTRODUCTION

In recent years, in world literature appeared research, which focuses on the study of relationships craniotypes with odonto-metric indicators, size, shape of the dental arches and occlusion. However, most of the experts focus on the study of individual features of the structure of the teeth-jaw system in people with different types of faces and aspects of sexual dimorphism and ethnic characteristics. Studies containing information about cranio-typological variability of the roots of teeth we did not encounter. The aim is to reveal features length of roots of incisors and canines of the upper and lower jaw, according to the CT scan in boys and girls of different craniotypes with physiological bite, residents Podilskiy region of Ukraine.

MATERIAL AND METHODS

The study involved young men with orthognathic bite and their cephalometric performance taken from database from Scientific and Research Center Vinnitsa National Medical University named after Pirogov. To make CT used dental cone beam CT scan - Veraviewepocs 3D, Morita. In the upper and lower incisors and canines were measured vestibular-oral and mesio-distal projection length of the root. The height (length) of the root was measured in the medial (or distal) norm, focusing on border basics crowns (root) and the apex of the tooth root. Established the following distribution craniotype: mesocephalic boys - 16, boys brachycephalic - 19, mesocephalic girls - 16, brachycephalic girls- 26. Statistical analysis of the results was performed using the statistical software package licensed "Statistica 6,0" using non-parametric estimation methods.

RESULTS

The peculiarities computed tomographic characteristics of root length incisors and canines of the upper and lower jaws in boys and girls Podilskiy region of Ukraine with different craniotypes and physiological bite have been set. In boys or girls mesocephals majority values of vestibular-oral and mesio-distal projection length of the teeth root, medial and lateral incisors in the upper and lower jaws significantly higher compared to studied similar gender brachycephals. Most values vestibular-oral and mesiodistal projection length of the teeth root, medial and lateral incisors in the upper and lower jaws in boys of total group and brachycephals significantly higher compared with girls of similar comparison groups. In boys mesocephals only value of vestibular-oral projection length of teeth root on the lower jaw was significantly higher compared with girls of the same craniotype.

CONCLUSIONS

In mesocephalic boys or girls majority values of vestibular-oral and mesio-distal length projection of the root teeth, medial and lateral incisors on the upper and lower jaws significantly higher compared to similar brachycephalic genders studied.

Assessment of gingival symmetry with digital measuring tools and its reproducibility

OBJECTIVE

The aim of this study was to investigate the accuracy of digital measuring tools to measure the position of gingival zeniths and to assess its reproducibility between different examiners.

MATERIALS AND METHODS

A total of 108 subjects were photographed at the Louisiana State University School of Dentistry. The settings, positioning of the digital camera, and subjects' Frankfurt levels were standardized. A photograph was taken of the six anterior maxillary teeth of each subject, and their corresponding free gingival margins. Digital caliper measurements were taken intraorally from the zenith to the incisal edge of the right maxillary central incisor. A reference line was drawn across the screen on each image at the level of the zenith of tooth 8. Three calibrated examiners then measured the distance from the reference line to the zeniths of the other five anterior maxillary teeth.

RESULTS/CONCLUSIONS

There was no statistically significant difference between the examiners regarding any of the measurements. Central incisors were at the same level in 84.24% of the subjects, and lateral incisors were within 0.5 mm of central incisors in only 58% of the subjects. Canine zeniths were within 0.5 mm of each other in 43% of the subjects. Only 28% of the subjects presented with zeniths of tooth 6 to tooth 11 within 0.5 mm of each other. Lateral incisors were at or beneath the line drawn from central incisors to cuspids in 90.8% of the subjects. Standardized digital photography taken with the aid of a stadiometer and used to evaluate esthetic parameters allowed for reproducible measurements.

Impact of Endodontic Treatments on the Rigidity of the Root

The destabilizing effect of endodontic treatment upon teeth is still controversial. The purpose of this study was to investigate the effects of different steps of endodontic treatments upon the rigidity of teeth. Extracted untreated central maxillary anterior teeth were loaded (3.75 N), and deformations of the root were assessed by Speckle pattern interferometry. The following treatments (with subsequent determination of deformability) were conducted sequentially: access preparation, manual instrumentation (Kerr files ISO-40, ISO-60, ISO-80, ISO-110), and tapered and parallel-sided post preparation. It was found that the teeth were increasingly destabilized by any treatment. While the increased deformability was not significant with the manual enlargement (p > 0.05), we found a significant destabilization after access preparation and post preparation (p < 0.05). A corresponding difference was found after conversion of the post preparation from tapered to parallel-sided (p < 0.05). Both substance loss and modifications of the natural root canal geometry play an important role in tooth rigidity.

In Vivo Color Relationships Between the Maxillary Central Incisors and Canines as a Function of Age

PURPOSE

It has long been taught that the hue of a patient can be taken from the canine and applied to other anterior teeth at a lower chroma. This concept does not appear to derive from published work. This study examined color relationships between in vivo maxillary central incisors and canines as a function of age.

MATERIALS AND METHODS

The L*a*b* values and VITA Classical shades of the maxillary central incisor and canine of 62 subjects were determined using a handheld spectrophotometer. Linear regression analysis and t tests were used to describe the relationships of the L*a*b* values of these teeth within each patient and as a function of age.

RESULTS

Linear regression demonstrated a significant decrease in ΔE with age (P = .056). Patient age was greater when ΔE (central-canine) > 3.3 (average age = 38.8 years) than when ΔE < 3.3 (average age = 58.8 years) (t test; P = .19). ΔC decreases significantly with age (P < .001). ΔH demonstrated a trend to decrease as a function of age (P = .2). ΔL remained the same over time (P = .21). Changes with age were due to central incisor differences, while the canine remained constant.

CONCLUSION

ΔE (incisor-canine) significantly decreases with age; mostly due to ΔC. The majority of changes for all three color coordinates are due to alterations in the central incisor. The majority of the patients in this study were found to have a different shade family (VITA Classical) for the central incisor and canine.

Canines mesiodistal measures as the key to sex prediction: a systematic review and meta-analysis

INTRODUCTION

The purpose of this study was to systematically review the literature about canine measures to determine whether their variations had any role in sex determination.

EVIDENCE ACQUISITION

The study searched MEDLINE database from 2004-2014 according PRISMA guidelines. Search terms included "canine teeth," "dental crowns," "dentition," "permanent," "sex dimorphism," "forensic anthropology," "review literature."

EVIDENCE SYNTHESIS

Four hundred forty-three studies were identified in the search strategy and 11 were included. Eight analysed mean differences of maxillary right canines' mesiodistal (MD) measures between male and female. There was no significant mean difference in two studies of eight (standardised mean difference [SMD]=0.150 and 0.268, respectively). According to all eight studies that reviewed them, maxillary right canines MD measures mean difference was significantly different (SMD=0.479). All five studies, which described maxillary left canines MD measures, found the mean, were significantly different (SMD=0.424). Ten studies found the same result for mandibular right canines (SMD=0.696). Eight studies found mandibular left canines MD measures and mean significantly different (SMD=0.685).

CONCLUSIONS

The most significant SMD was between male and female mandibular canines (right and left), mesiodistal width 0.696 and 0.685 respectively. Consequently, these canines are the most important to the sex prediction.

Maxillary sinus volume in patients with impacted canines

OBJECTIVES

To evaluate the maxillary sinus volumes in unilaterally impacted canine patients and to compare the volumetric changes that occur after the eruption of canines to the dental arch using cone beam computed tomography (CBCT).

MATERIALS AND METHODS

Pre- (T0) and posttreatment (T1) CBCT records of 30 patients were used to calculate maxillary sinus volumes between the impacted and erupted canine sides. The InVivoDental 5.0 program was used to measure the volume of the maxillary sinuses. The distance from impacted canine cusp tip to the target point on the palatal plane was also measured.

RESULTS

Right maxillary sinus volume was statistically significantly smaller compared to that of the left maxillary sinus when the canine was impacted on the right side at T0. According to the T1 measurements there was no significant difference between the mean volumes of the impaction side and the contralateral side. The distance from the canine tip to its target point on the palatal plane were 17.17 mm, and the distance from the tip to the target point was 15.14 mm for the left- and right-side impacted canines, respectively, and there was a significant difference between the mean amount of change of both sides of maxillary sinuses after treatment of impacted canines.

CONCLUSIONS

Orthodontic treatment of impacted canines created a significant increase in maxillary sinus volume when the impacted canines were closer with respect to the maxillary sinus.

Orthodontists' and laypeople's perception of smile height aesthetics in relation to varying degrees of transverse cant of anterior teeth

AIMS

To determine the effect of varying the transverse cant of the anterior teeth on orthodontists' and laypeople's perceptions of smile aesthetics, and the influence that smile height has on this perception.

MATERIALS AND METHODS

A 20-year-old Chinese female with an aesthetic smile and normal occlusion was chosen and agreed to participate. Digital pictures of her posed smile were taken and manipulated to create three smile height variations: low, medium, or high. Each variation was further manipulated to create varying degrees of transverse anterior tooth cant. Fifty-six laypeople and 40 orthodontists participated as raters of the dental and facial impact of the altered smile images.

RESULTS

The orthodontists more commonly and precisely identified the transverse cants of the anterior teeth and the detracting influence on smile aesthetics compared with laypersons. The orthodontists accepted a lesser range of anterior transverse cant. Increased smile heights enhanced the capability of all raters to detect a transverse cant and reduced the acceptable cant range. In addition, an increased smile height worsened the detracting effects of the transverse anterior cant in all raters' perceptions of smile aesthetics. An increased display of teeth and angulation of an anterior cant increased the ability of raters in both groups to detect differences.

CONCLUSION

Transverse cants of anterior teeth can affect orthodontists' and laypeople's perceptions of smile aesthetics. Smile height and incisor display were significant factors that affected the orthodontist's and layperson's perceptions of smile aesthetics, and suggested that a description of the detracting effect of an anterior transverse cant should also consider smile height.

CLINICAL RELEVANCE

A transverse occlusal cant is an important aesthetic factor used by clinicians during orthodontic diagnosis and review. It is important to appreciate that there is a difference in perception between orthodontic professionals and patients (laypeople). The extent of this perceptual difference and influencing factors could help the clinician set more appropriate treatment goals.

Sexual Dimorphism in the Dimensions of Teeth in Serbian Population

The study of teeth is of great interest to anthropologists, biologists, orthodontists and forensic scientists. The existence of sexual dimorphism in permanent teeth is a known phenomenon. Aim of this study was to analyze the presence of sexual dimorphism in the mesiodistal and vestibulolingual diameter of permanent teeth in the sample of Serbian population. Measurements were taken on plaster casts of 201 individuals of both sexes, ages between 18-25 years, using a digital caliper with 0.01 mm precision. The mesiodistal and vestibulolingual diameter of each permanent tooth was determined. A Student's t-test and a Mann-Whitney U test were used to statistically analyze the obtained results. There were no statistically significant differences in the teeth crown diameter between the right and left side of the same dental arch. Majority of the teeth examined were larger in male than in female patients. Statistically significant difference in the mesiodistal diameter of male and female maxillary and mandibular canines was found. The results of this study indicate that there are significant differences in teeth size between sexes in Serbian population. Males have larger diameters in teeth crowns than females. Canines show the greatest dimorphism.

The anterior component of occlusal force revisited: direct measurement and theoretical considerations

BACKGROUND

The anterior component of occlusal force (ACF), considered to result from the mesial inclination of teeth relative to the occlusal plane, has been estimated by indirectly measuring contact point tightness (CPT) through interproximal insertion of metal strips. ACF has been observed concurrently with a posterior component, whose theoretical origin is difficult to explain.

OBJECTIVES

Evaluate ACF by measuring CPT directly, and integrate current data to propose a theoretical basis for ACF.

MATERIALS AND METHODS

The sample comprised 14 females (age: 22.3±2.8) and 16 males (age: 20.8±2.5). Our device consisted of two force sensors: one for measuring maximum bite force (MBF) (overall thickness: 4mm), and one for measuring CPT directly (0.2mm thick), inserted between the lower first molar and second premolar. ACF was computed as the difference in CPT between the biting (at 75 per cent of MBF) and non-biting conditions.

RESULTS

Averages of MBF, CPT, and ACF were 666.67 [standard deviation (SD): 36.06], 6.74 (SD: 1.17), and 20.59 (SD: 4.60) N, respectively. ACF, CPT, and MBF were higher in males by approximately 28, 18 and 7 per cent, respectively. A positive correlation was observed between ACF and MBF (R (2): 0.64). CPT was also significantly correlated to MBF (R (2): 0.40). Biomechanical analysis indicates that previously offered explanations do not unriddle the concurrent increase of CPT at anterior and posterior contact points.

CONCLUSIONS

ACF was related to bite force by a logarithmic model. We speculate that CPT increases during biting through a combination of mesial tipping of teeth and mandibular bending.

Characteristics of Teeth: A Review of Size, Shape, Composition, and Appearance of Maxillary Anterior Teeth

Although digital technologies play an increasingly integral role in dentistry, there remains a need for dental professionals to understand the fundamentals of tooth anatomy, form, occlusion, and color science. In this article, the size, shape, composition, and appearance of maxillary anterior teeth will be discussed from esthetic and functional perspectives. A total of 600 extracted maxillary incisors were studied: 200 each of central incisors, lateral incisors, and cuspids. The purpose of the article is to exhibit and discuss factors that make teeth unique and diverse. Understanding these aspects of teeth aids dental professionals in more effectively creating realistic and highly esthetic restorations for patients.

A Morphometric Study of Labial Grooves on Anterior Maxillary Dentition

This study was performed to investigate the shape, characteristics, and correlation of labial grooves on anterior maxillary dentition. Individual teeth (N = 621) were investigated using a microscopic three-dimensional digital image correlation system. The average length, width, and depth of grooves were quantified, and groove patterns in anterior maxillary teeth and the symmetry and correlation of grooves in anterior maxillary dentition were studied. There were nine common groove patterns in central incisors, eight in lateral incisors, and nine in canines. A good symmetry of grooves was found between the left and right dentition. The number of grooves and the groove pattern were correlated among central incisors, lateral incisors, and canines. This study may provide guidance for clinical design of labial grooves.

[Root anatomy and root canal morphology of mandibular canines in Israeli population]

INTRODUCTION

Furcated root and root canal separation are anatomic variations of mandibular canines. Other studies found that up to 20% of mandibular canines have root canal separation and up to 6.8% are bifurcated teeth. The purpose of this study was to investigate the prevalence of two-rooted mandibular canines and the root canal morphology of mandibular canines.

METHODS

A total of 1,020 Israeli patients' cone-beam computed tomography (CBCT) scans were screened and evaluated. A total of 1,981 mandibular canines were examined and the prevalence of furcated mandibular canines and root canal separation was recorded and analyzed.

RESULTS

The overall prevalence of furcated mandibular canines and root canal separation in mandibular canines were 1.9% and 10.3% respectively. The bilateral prevalence of furcated mandibular canines was 22.5%. Statistically significant difference was detected by the side of occurrence (left vs right side, p < 0.05) and by gender in right mandibular canine (p < 0.05).

CONCLUSION

the prevalence of furcated roots and root canal separation in mandibular canines was not frequent. Clinicians should be aware of the special characteristic of those anatomic variations.

Canine guidance via Biogeneric Copy: a clinical report

The advent of computer-aided design/computer-aided manufacturing (CAD/CAM) technology in dentistry has enabled a wide range of applications. The Cerec Acquisition Center (Cerec AC, Sirona Dental Systems Inc., Charlotte, NC) allows for the construction of all-porcelain restorations, either in-office or through a remote dental laboratory. One feature of the Cerec AC is its ability to duplicate the dental morphology of an existing tooth onto a new CAD/CAM ceramic restoration designed for that tooth. This design mode capability of the Cerec AC is termed Biogeneric Copy. This function has been discussed in the literature where it has been utilized to fabricate a CAD/CAM ceramic crown to fit an existing removable partial denture (RPD).1-3 There are occasions in dentistry where the exact anatomy and position of an existing tooth, not associated with an RPD, should ideally be replicated in a definitive restoration. This case report describes such an occasion.

A new approach to sex estimation using the mandibular canine index

Rao et al.'s mandibular canine index (MCI) is a simple odontometric method which uses the mandibular canine as the key to sex estimation. This index is defined as the ratio between the right canine mesiodistal dimension and the mandibular canine arch width. The aim of this study was to contribute to sex estimation using dental techniques by analysing the MCI efficiency, and to propose a new approach for its use. Measurements were taken from 120 plaster casts (70 females) in the 16-30 year age group. Although statistically significant sexual dimorphism was observed in both the mesiodistal dimension and the mandibular canine arch width, the MCI showed a low accuracy in sex classification (54.2% correct identifications). This accuracy was improved to 64.2% using receiver operating characteristics curve analysis. Yet, despite the better accuracy, these results reinforce the idea that the MCI may not be particularly useful in sex prediction, since it may not reflect the same degree of sexual dimorphism as its absolute measures.

Treatment planning of adhesive additive rehabilitations: the progressive wax-up of the three-step technique

A full-mouth rehabilitation should be correctly planned from the start by using a diagnostic wax-up to reduce the potential for remakes, increased chair time, and laboratory costs. However, determining the clinical validity of an extensive wax-up can be complicated for clinicians who lack the experience of full-mouth rehabilitations. The three-step technique is a simplified approach that has been developed to facilitate the clinician's task. By following this technique, the diagnostic wax-up is progressively developed to the final outcome through the interaction between patient, clinician, and laboratory technician. This article provides guidelines aimed at helping clinicians and laboratory technicians to become more proactive in the treatment planning of full-mouth rehabilitations, by starting from the three major parameters of incisal edge position, occlusal plane position, and the vertical dimension of occlusion.

Accuracy of four different digital intraoral scanners: effects of the presence of orthodontic brackets and wire

OBJECTIVE

The objective of this study was to compare the accuracy of four different digital intraoral scanners and the effects of buccal brackets and orthodontic wire.

METHODS

For this study, three sets of models (Control model, BKT model with buccal bracket, and WBKT model with buccal bracket and orthodontic wire) were scanned using four different types of intraoral scanners: E4D dentist, iTero, Trios, and Zfx IntraScan. The mesiodistal width of the teeth, intercanine width, and intermolar width measured by four scanners were compared. Three-dimensional (3D) images of the brackets were taken using the four scanners. Data were analyzed with one-way ANOVA, independent t test, and post-hoc Tukey test at a significance level of P < 0.05.

RESULTS

When comparing the 3D images with manual measurements using a traditional caliper, iTero and Trios showed the highest accuracy in horizontal measurements.iTero had the lowest values in Devmax-min of maxillary intermolar and intercanine widths (0.16 mm and 0.20 mm, respectively), whereas Trios had the lowest values in Devmax-min of mandibular intermolar and intercanine widths (0.36 mm and 0.14 mm, respectively). The horizontal variables were barely affected by the presence of buccal brackets and orthodontic wire. Comparison of 3D bracket images scanned by the four scanners showed differences in image distortion among the scanners. Bracket characteristics did not affect the 3D bracket images.

CONCLUSIONS

The four intraoral scanners used in this study differed in accuracy. However, the results acquired by iTero and Trios were more reliable. Effects of buccal brackets and orthodontic wire on the 3D images taken by intraoral scanners were not clinically significant.

Occlusal Characteristics of the Primary Dentition Revisited

The occlusal characteristics of the primary dentition of 130 children 3 to 6 years old were examined. Variables were the terminal plane relationship, primary canine occlusion, spacing, overjet and overbite relationships. The flush terminal plane was the most common finding. A Class I relationship of the primary canine occurred in 85% of the subjects. Spaced dentitions occurred 81% of the time, while the presence of primate spaces occurred in at least one of the four quadrants. The overjet relationship varied from +1 mm to 4 mm in all subjects, and the majority of children were considered to have a normal overbite.

ANATOMO-MORPHOLOGICAL FEUTURES OF THE ROOT CANAL SYSTEM IN GEORGIAN POPULATION - CONE-BEAM COMPUTED TOMOGRAPHY STUDY

Incomplete and superficial knowledge of morphological types and anatomical variations of the root canal system will become the reason leading to the failure of endodontic treatment. cone-beam computed tomography (CBCT) - it is a technologically more sophisticated, interesting, reliable, non-invasive imaging technique with high degree of visualization, considered as a particularly important and useful tool to study complexity and variability of canal system. 2753 teeth of 228 patients have been studied by CT. Ages of the patients varied within 25-55 years. Among them 122 men and 106 women. Maxillary teeth - 1394 and mandibular - 1359, respectively. The aim of our study was investigation and evaluation of: tooth length, number of roots and canals, type of configuration, root canal curvature and degree of curvature in Georgian population. The results of the study revealed interesting data and anatomical characteristics, those replicating the racial signs and differs from the data recorded by the other researchers, became evident. In studying of dental form variations were interested anatomists (description and comparison) anthropologists, biologists, palaeontologists and stomatologists. The field of human dental anatomy has not been completely explored so, the modern human teeth still remain a matter of continual curiosity and research. The knowledge of anatomical characteristics of dental root canals will help clinicians to optimize the algorithm of endodontic treatment. Thus, statistic data are not the universal criterias, however, basing on these indicators anthropometrical data of roots and canals vary according to the geographic zones and nationalities. The study of variations in tooth form has interested anatomists (description and comparison), anthropologists, biologists, palaeontologists and dentists. The field of human dental anatomy has not been completely explored and the dentition of modern man still remains a matter of continual curiosity and research. Thus, statistic data are not the universal criterias, however, basing on these indicators anthropometrical data of roots and canals vary according to the geographic zones and nationalities. The study of variations in tooth form has interested anatomists (description and comparison), anthropologists, biologists, palaeontologists and dentists. The field of human dental anatomy has not been completely explored and the dentition of modern man still remains a matter of continual curiosity and research.

Periodontal health of anterior teeth with two types of fixed retainers

OBJECTIVE

To compare the periodontal health of maxillary and mandibular anterior teeth retained with two types of fixed retainers.

MATERIALS AND METHODS

A fixed straight retainer (SR) group had 39 subjects, and a fixed wave retainer (WR) group had 35 subjects. Subjects were between the ages of 13 and 22 years and had been in fixed retention for 2 to 4 years. Pocket probing depths, bleeding on probing, plaque index, calculus index, recession, and gingival crevicular fluid volume were compared between the two retainer groups. A four-question oral hygiene survey was given to each subject. The Mann-Whitney U-test and Fisher exact test was used to analyze the data.

RESULTS

There was no clinically significant difference between the retainer groups regarding plaque index, gingival crevicular fluid volume, calculus index, recession, bleeding on probing, and pocket probing depths. A statistically significant increase in the reported frequency of flossing (P  =  .006) and ease of flossing (P < .001) was associated with the WR group. There was no significant difference between the groups in reported frequency of brushing and comfort of the retainer.

CONCLUSIONS

Under the conditions of this study, no clinical difference was found in the periodontal health of anterior teeth retained with a SR or WR for a period of 2 to 4 years. Subjects in the WR group reported an increase in frequency and ease of flossing.

Correlation of maxillary anterior tooth width and outer intercanthal distance

The selection of the correct maxillary anterior teeth to establish proper mesiodistal width in a prosthesis is one of the most crucial phases of prosthodontic treatment. The ratio of facial measurements to natural tooth width could be considered a helpful scale. The aim of this study was to explore the relationship between outer intercanthal distance (OICD) and the combined anterior width (CAW) of maxillary teeth. The CAW between the canine distal contacts and the OICD of 100 men and 100 women were measured. Pearson correlation coefficients demonstrated a positive correlation between OICD and CAW. There was no statistically significant difference between the sexes in mean difference between OICD and CAW. Within the limitations of this study, the results suggest that the OICD can be used as a fairly reliable method to determine the CAW for edentulous patients.

Canine length in wild male baboons: maturation, aging and social dominance rank

Canines represent an essential component of the dentition for any heterodont mammal. In primates, like many other mammals, canines are frequently used as weapons. Hence, tooth size and wear may have significant implications for fighting ability, and consequently for social dominance rank, reproductive success, and fitness. We evaluated sources of variance in canine growth and length in a well-studied wild primate population because of the potential importance of canines for male reproductive success in many primates. Specifically, we measured maxillary canine length in 80 wild male baboons (aged 5.04-20.45 years) from the Amboseli ecosystem in southern Kenya, and examined its relationship with maturation, age, and social dominance rank. In our analysis of maturation, we compared food-enhanced baboons (those that fed part time at a refuse pit associated with a tourist lodge) with wild-feeding males, and found that food-enhanced males achieved long canines earlier than wild-feeding males. Among adult males, canine length decreased with age because of tooth wear. We found some evidence that, after controlling for age, longer canines were associated with higher adult dominance rank (accounting for 9% of the variance in rank), but only among relatively high-ranking males. This result supports the idea that social rank, and thus reproductive success and fitness, may depend in part on fighting ability mediated by canine size.

Anterior tooth alignment: A comparison of orthodontic retention regimens 5 years posttreatment

OBJECTIVE

To assess orthodontic treatment outcome at debonding and at 3 and 5 years after orthodontic treatment and to investigate the influence of different retention protocols on anterior tooth alignment.

MATERIALS AND METHODS

Using the Peer Assessment Rating (PAR) Index, 169 patients (74 boys, 95 girls) were analyzed at four stages: pretreatment (T0), posttreatment (T1), 3 years posttreatment (T3), and 5 years posttreatment (T5). The PAR anterior component scores (ACSs) were compared between groups with different retention protocols. In the maxilla, protocols were removable retainer until T3 (MAX1), removable and fixed retainer until T3 (MAX2), and removable retainer until T3 and fixed retainer until T5 (MAX3). In the mandible, protocols were no retainer (MAND1), fixed 3-3 retainer until T3 (MAND2), and fixed 3-3 retainer until T5 (MAND3).

RESULTS

Mean weighted improvement in PAR score was 88.3% at T1, 86.4% at T3, and 82.1% at T5. The ACS for the maxilla showed no significant differences between the retention protocols at any time point. In the mandible, the group without retention showed a gradual but not significant deterioration in ACS throughout the posttreatment period. At T5 there was a significant difference in ACS between the group that had the retainer removed at T3 and the group that kept the retainer.

CONCLUSION

The 5-year treatment outcome, as measured by the PAR Index, was good. Stability of the maxillary anterior alignment 5 years posttreatment did not appear to be influenced by choice of retention protocol. Mandibular anterior alignment was significantly better for the group using a fixed retainer compared with the group where the retainer was removed 3 years posttreatment.

MIXED DENTITION SPACE ANALYSIS OF A SOUTHERN ITALIAN POPULATION: NEW REGRESSION EQUATIONS FOR UNERUPTED TEETH

Mixed dentition analysis forms a critical aspect of early orthodontic treatment. In fact an accurate space analysis is one of the important criteria in determining whether the treatment plan may involve serial extraction, guidance of eruption, space maintenance, space regaining or just periodic observation of the patients. The aim of the present study was to calculate linear regression equations in mixed dentition space analysis, measuring 230 dental casts mesiodistal tooth widths, obtained from southern Italian patients (118 females, 112 males, mean age 15±3 years). Student’s t-test or Wilcoxon test for independent and paired samples were used to determine right/left side and male/female differences. On the basis of the sum of the mesiodistal diameters of the 4 mandibular incisors as predictors for the sum of the widths of the canines and premolars in the mandibular mixed dentition, a new linear regression equation was found: y = 0.613x+7.294 (r= 0.701) for both genders in a southern Italian population. To better estimate the size of leeway space, a new regression equation was found to calculate the mesiodistal size of the second premolar using the sum of the four mandibular incisors, canine and first premolar as a predictor. The equation is y = 0.241x+1.224 (r= 0.732). In conclusion, new regression equations were derived for a southern Italian population.

Functional occlusal patterns during lateral excursions in young adults

STATEMENT OF PROBLEM

A valid system for assessing and classifying functional occlusion has not been established. The prevalence of anterior protected articulation is not known.

PURPOSE

The purpose of this study was to quantify the prevalence of various functional occlusal contact patterns, including anterior protected articulation, among dental students.

MATERIAL AND METHODS

Occlusal contacts were examined during lateral excursions from the maximal intercuspal position to the canine-to-canine position in 100 young adults. A combination of 3 common clinical methods was used: a visual examination, articulating paper, and feedback from the participants.

RESULTS

Data from 3 classification systems were analyzed: (1) Occlusal contacts on the working side only – canine protected articulation was present in 25% of laterotrusions; anterior protected articulation was present in 18.5% of laterotrusions. Group function was present in 56% of laterotrusions. Other schemes were present in 0.5% of laterotrusions. (2) Contacts on both the working and the nonworking side. (3) Contacts on the working and nonworking side during both right and left laterotrusion. Nonworking side contacts were present in 33% of the participants. Nonworking side interference was present in 1 participant.

CONCLUSIONS

The prevalence of anterior protected articulation found in this study was high enough to allow anterior protected articulation to be considered one of the fundamental working side occlusal contact patterns. More studies will be necessary to confirm this finding.

Influence of tooth length on the accuracy of the Root ZX electronic apical foramen locator: an ex vivo study

OBJECTIVE

Electronic apical foramen locators are now widely used to determine working length. This study was designed to determine whether tooth length influenced the accuracy of the Root ZX device.

MATERIALS AND METHODS

Forty extracted maxillary canine teeth with a length range of 27-29 mm were selected. Access cavities were prepared and coronal flaring of canals performed. The teeth were mounted in self-polymerizing acrylic resin to facilitate horizontal sectioning except for the apical 3-4-mm portion of the root and embedded in alginate as the electronic medium. Electronic measurements were taken at the major foramen, 'zero' reading using the Root ZX and compared with the actual root canal length. The teeth were sectioned 3 mm from the coronal reference point to create a second group with shorter length; these reductions in the length continued six times in all to create seven groups of 40 specimens each. The actual and electronic lengths of specimens in each group were measured. Data were analyzed by Pearson's correlation coefficient.

RESULTS

Identical measurements between the actual and electronic root canal length from the longest to the shortest groups were 12.5%, 10.0%, 20.0%, 27.5%, 37.5%, 35.0% and 45.0%, respectively. There was a mild negative correlation between the precise measurements of the Root ZX and root canal lengths in the seven groups (r = -0.964, p < 0.001).

CONCLUSION

Under the conditions of the study, the Root ZX device was more accurate in shorter teeth compared to longer ones.

Applicability of the Tanaka-Johnston and Moyers mixed dentition analyses in Northeast Han Chinese

OBJECTIVES

To assess applicability of the Tanaka-Johnston and Moyers prediction methods in a Han ethnic group from Northeast China and to develop prediction equations for this same population.

DESIGN

Cross-sectional study.

SETTING

Department of Orthodontics, School of Stomatology, Jiamusi University, Heilongjiang, China.

PARTICIPANTS

A total of 130 subjects (65 male and 65 female) aged 16-21 years from a Han ethnic group of Northeast China were recruited from dental students and patients seeking orthodontic treatment. Ethnicity was verified by questionnaire.

MATERIAL AND METHODS

Mesio-distal tooth width was measured using Digital Vernier calipers. Predicted values were obtained from the Tanaka-Johnston and Moyers methods in both arches were compared with the actual measured widths. Based on regression analysis, prediction equations were developed.

RESULTS

Tanaka-Johnston equations were not precise, except for the upper arch in males. However, the Moyers 85th percentile in the upper arch and 75th percentile in the lower arch predicted the sum precisely in males. For females, the Moyers 75th percentile predicted the sum precisely for the upper arch, but none of the Moyers percentiles predicted in the lower arch.

CONCLUSIONS

Both the Tanaka-Johnston and Moyers method may not be applied universally without question. Hence, it may be safer to develop regression equations for specific populations. Validating studies must be conducted to confirm the precision of these newly developed regression equations.

Gingival biotype characterization--a study in a Portuguese sample

BACKGROUND

Establishing the diagnosis of a particular clinical situation in the oral cavity must take many characteristics into consideration, with gingival phenotype being an important one because it is linked to every individual's gingival morphogenic characteristics, including soft tissue appearance, genetic characteristics, and the way the gingiva looks after manipulation.

MATERIALS AND METHODS

In this study, 294 patients were observed. Fifty patients were selected according to certain exclusion criteria. Patients were submitted to clinical intraoral examinations, and photographs were taken of the anterior maxillary area. Comparing the left and right sides of the anterior maxillary area, the variables analyzed were the crown width/crown length ratio, papilla height, gingival width, gingival thickness, gingival angle, and gingival asymmetry.

RESULTS

A statistical relation between gender and gingival thickness was not proven (P>0.05), neither was that between shape and gingival thickness. However, this relation has statistical significance to gingival thickness and all analyzed variables (P<0.001), as well as gender and papilla height (P=0.005), crown width/crown length ratio (P=0.017), and gingival angle (P=0.041). A positive relation between the GLA angle measured from both sides was also found (correlation=0.675), as well as for LID values (correlation=0.384). The absolute asymmetry value was 2.8 degrees, showing different measurements from each dental arch side.

CONCLUSION

Within the limitations of this study, it can be concluded that there is a strong association between gender and the following variables: crown width/ crown length ratio, papilla height, and gingival angle. It was also demonstrated that a correlation exists between gingival thickness and all the variables studied. Moreover, the influence of tooth form on the gingival characteristics studied was demonstrated.