Mesiodistal Research Articles

Correlation between maxillary central incisor crown form and maxillary dental arch form: A Model-Based morphometric, cross-sectional study

The crown form of maxillary central incisor tooth is one of the vital phenomenon for a person's esthetics. Its crown form has been compared with other anatomical parameters such as arch form and facial form. Three different classes of tooth forms which relate to square, tapered, and ovoid forms are identified. The aim of this study was to morphometrically evaluate the correlation between maxillary dental arch form and the maxillary central incisor crown form. Dentate cast models of fifty male and fifty female normal occlusion controls in the age group of 18–23 years were analyzed. The mesiodistal (MD) dimensions of the maxillary central incisors were measured at incisal (MD_I) and at gingival (MD_G) levels. The transverse widths of maxillary casts were measured at the first molar and at the first premolar levels. The measured data were statistically analyzed using the SPSS software. The MD dimensions of maxillary central incisor were significantly greater in males than females. The ratio between the two MD dimensions also varied significantly among genders. The intermolar width (IMW) and inter first premolar width (IPmW) between males and females were highly significant (P

Palatoscopy and odontometrics for sex identification and hereditary pattern analysis in a Navi Mumbai population: A cross-sectional study.

Background:Identification of an individual is a challenging task in the field of forensic odontology. Sometimes, the identity of individuals by fingerprints is difficult; hence, the examination of palatal rugae and the human dentition is a viable option.Aims and Objectives:The objective of the present study was to determine the sex of an individual and the hereditary pattern using three parameters are as follows: palatine rugae, dimensions of maxillary molar and maxillary canine.Materials and Methods:A cross-sectional study involved a total of 200 participants which included 60 males, 60 females and 20 families with four members each. Maxillary impressions were made with elastomeric impression material, and dental stone was used to make the models. The parameters used were as follows: palatine rugae classified by Thomas and Kotze (1983), which included the shape, size, direction and unification pattern, mesiodistal (MD) width of canines and intercanine width and MD and buccolingual width of maxillary molars.Statistical Analysis:Unpaired t-test and the median test were used to assess the sex differences in the number and unification pattern for the palatal rugae and to compare dimensions measured for males and females for the odontometric data. The data collected was statistically analyzed using the Statistical Package for Social Sciences 17.0 statistical program for windows. The statistical significance was fixed at 0.05.Results:Males showed more number of converging rugae and females showed more number of diverging patterns of rugae. The number of primary and forward rugae was more in both the genders and females showed more wavy rugae while males showed more number of straight and curved rugae. The maxillary canine and maxillary molar dimensions both were more in males than the females and also none of these parameters showed a hereditary pattern.Conclusion:Rugae pattern and the human dentition are both highly individualistic and can be used for personal identification and sex determination.

Employing Dimensional Disparity of Teeth to Establish the Gender in Odisha Population: A Dimorphic Study.

Aims and Objectives:Determination of sex is one of the most important and crucial steps in forensic science. Sexual dimorphism using odontometric analysis is found to vary in different populations making it necessary to attain values of a specific population which helps the identification possible. This present study attempts to establish sexual dimorphism using odontometric analysis in Odisha population.Materials and Methods:A total of 200 subjects (100 male and 100 female) between ages 18 and 25 years were included in the study. Intraoral Mesiodistal (MD) and Buccolingual (BL) dimensions of 28 teeth (maxillary and mandibular) excluding third molar were taken using digital Vernier calipers. Data were charted and decrypted and statistical analysis was done using SPSS Software version 20.Results:Our study showed larger dimensions of tooth in males when compared to females (maxillary right and left central incisor, 1st and 2nd molar). Interestingly, reverse dimorphism was also observed in few teeth.Conclusion:The results of the present study showed that the linear (MD and BL) dimensions of teeth played a major role in the determination of gender in individuals. The variations or reverse dimorphism could be a result of geographic variations.

Odontometry and skull anthropometry: A possible tool for stature estimation using minimum armamentarium

Introduction: In the Asia Pacific region, because of variation in topography and climatic conditions, India is a disaster-prone country. The identification of an individual is one of the most important aspects of forensic medicine. There are different methods for identification of a person's age and gender. However, there are relatively fewer methods to estimate the stature of an individual. Stature correlation to skull and jaw dimensions is less frequently reported. The aim of the study is to investigate the relationship between height of the person and diameter of the head (DH) and circumference of the head with the combined mesiodistal (MD) width of maxillary anterior teeth using minimum and easily available armamentarium. Materials and Methods: Fifty model casts of students were considered to measure the MD width of the anterior teeth along with the circumference of the head and DH (distance from glabella to inion) with the help of a nonstretchable measuring tape. Heights of the students were recorded in inches. All the findings were tabulated and statistically analyzed. Observations and Results: When combined MD width of the maxillary anterior teeth was plotted against height, a statically significant correlation was seen. When head circumference was plotted against height, a higher correlation was seen. When two measurements were added and plotted against height, improved elevated correlation was seen. Similarly, when the MD width was added to circumference of the head and DH, a greater correlation was observed. Conclusion: It can be safely concluded that with more data to prove the study, a formula can be drawn to estimate the height of the person using MD width of the anterior teeth, DH, and circumference of the head.

A comparative study of cone-beam computed tomography and intrasurgical measurements of intrabony periodontal defects

Objective: The objective of this study was to analyze the correlation between cone-beam computed tomography (CBCT) measurements and intrasurgical measurements of intrabony periodontal defects. Materials and Methods: Thirty-two patients with intrabony defects, who underwent periodontal therapy and were advised for surgical therapy, were included in this study. Diagnostic images were obtained by periapical radiographs and CBCT before the surgical procedure. The distance from the cementoenamel junction to the base of the periodontal defect (CEJ–BD), the distance from the crest of bone to the deepest point of the defect, and mesiodistal (M-D) width of the periodontal defect were measured on CBCT and periapical radiographs during the surgical procedure. The faciolingual width of the defect was only measured on CBCT images during the surgical procedure. The linear measurements obtained during the surgical therapy were compared with that obtained by intraoral radiographs and CBCT imaging. Results: The M-D width of the defect measured during the surgical procedure was similar to that measured on the periapical radiograph. The distance of CEJ to BD and the distance from the crest of bone to the deepest point of the defect measured on the periapical radiographs were less than that of intrasurgical measurements. No significant difference was noted regarding the CBCT measurements of the faciolingual width and M-D width of the defect when compared with the measurements obtained during the surgical procedures. A significant difference was noted in the CBCT measurements from the CEJ to BD and the distance from the crest of bone to the deepest point of the defect when compared with the intrasurgical measurements. Conclusion: CBCT may lend comparatively discriminative dimensions of the periodontal defect similar to that of intrasurgical measurements.

Radiographic and micro-computed tomography classification of root canal morphology and dentin thickness of mandibular incisors.

Context:Root canal anatomy is evaluated using different methodologies.Aims:The aim of this study is to evaluate and classify root canal morphology and dentin thicknesses (DT), comparing radiographic and micro-computed tomography (CT) analysis.Materials and Methods:Canal diameter and DT of mandibular incisors (n = 520) were evaluated using digital radiographs in buccolingual (BL) and mesiodistal (MD) directions. The diameter ratio (DR) BL/MD was classified: flattened (FL, DR >4); oval (OV, 2≤ DR ≥4); rounded (RN, 1.1< DR >2); round (RO, 0.9≤ DR ≥1.1); and with BL flatness (BL, DR <0.9). OV (n = 110) were subjected to micro-CT. DT and DR were evaluated at 3, 6, and 9 mm. ANOVA, Tukey, and paired Wilcoxon tests (P < 0.05) were used.Results:Radiographic classification was 23.3% FL, 41.3% OV, 27.3% RN, 4.5% RO, and 3.6% BL. DT was similar. Radiographic DT at 3 and 9 mm was greater than micro-CT (P < 0.05) and was similar at 6 mm (P > 0.05). DR differed between the analyses. Oval canals were predominant at all levels radiographically and at 9 and 6 mm in micro-CT analysis, with greater variation at 3 mm.Conclusion:Oval root canals are predominant in mandibular incisors at 9 mm. Radiographic DT is larger than observed in micro-CT at 3 and 9 mm, and the classification differed in each root level. The classification at 9 mm is indicated.

A Cone-beam Computed Tomographic Study of Apical Surgery–related Morphological Characteristics of the Distolingual Root in 3-rooted Mandibular First Molars in a Chinese Population

IntroductionApical surgery on the separate distolingual (DL) root of a 3-rooted mandibular first molar is thought to be difficult because DL roots are always severely curved, small, and shorter than distobuccal (DB) roots, and they are located far from the buccal cortical bone. The purpose of this study was to use cone-beam computed tomographic images to investigate the apical surgery–related morphological characteristics of DL roots in a Chinese population. MethodsThe screening process identified 83 subjects with 128 mandibular first molars with separate DL roots. The degree of root canal curvature was measured in the mesiodistal (MD) and buccolingual (BL) planes using the Schneider method. Distances were measured from the DL root apex to the buccal cortical bone, to the buccal cortical bone opposite the DB root apex, and to the buccal cortical bone opposite the mesiobuccal (MB) root apex. The lengths of the remaining DB, MB, and DL roots were measured after resection of 3 mm of the DL apical root. Angulations of the DL root canal were determined before and after DL apical root resection. ResultsThe teeth were classified into 3 types: type I, straight in the MD and BL planes; type II, straight in the MD plane and curved in the BL plane; and type III, curved in the MD and BL planes. Only 5 molars (3.9%) were classified as type I, whereas 52 (40.6%) molars were type II and 71 (55.5%) molars were type III. The type I DL root has a significantly shorter length and longer distance from the DL root apex to the buccal cortical bone than type II and III roots (P < .05). The distance from the DL root apex to the buccal cortical bone opposite the MB root apex is significantly longer than the distance to the buccal cortical bone opposite the DB root apex in types I and II (P < .05), whereas the distance is nearly equal for type III. The angulations for root-end preparation of types II and III DL roots vary from 57.5° to 129.1° and from 55.8° to 128.1°, respectively. ConclusionsA new classification was proposed for DL roots in 3-rooted mandibular first molars based on the root canal curvature. Type I is unsuitable for apical surgery. Access to the type II DL root apex should be through the DB root apex, whereas access to the type III DL root apex through the MB root apex is more feasible. Apical surgery on types II and III DL roots may be accomplished when the depth of the root-end preparation is reasonably reduced, and fine and personalized angulated ultrasonic retro tips are used.

Fluctuating dental asymmetry in rabbits with familial nonsyndromic coronal suture synostosis

Fluctuating dental asymmetry has been linked to conditions of unstable pre- and peri-natal development. Familial, nonsyndromic craniosynostosis disrupts early craniofacial development through localized excessive calvarial ossification leading to the premature fusion of the calvarial sutures. Such abnormal gene expression may also produce systemic stress resulting in developmental instability, thereby affecting normal trait symmetry. The present study was designed to test this hypothesis by examining fluctuating dental asymmetry in an inbred strain of rabbits with familial, nonsyndromic coronal craniosynostosis. The mesiodistal (MD) and buccolingual (BL) dimensions of the right and left maxillary first molars were measured in four groups of New Zealand white rabbits (N=176; n=40 with early-onset synostosis, n=65 with delayed-onset synostosis, n=46 in-colony, phenotypically normal rabbits, and n=25 wild-type normal controls). For each variable, raw signed asymmetry was calculated (left-right) and tested for assumptions of fluctuating asymmetry (i.e., normality and non-directionality). Any group that did not meet these assumptions was excluded from further analysis. Using a standard size-adjusted, fluctuating asymmetry index, mean fluctuating asymmetry was calculated and compared across groups with non-parametric statistics. For the MD dimension, no significant (p &gt; 0.05) group differences in mean fluctuating asymmetry were observed among groups. In contrast, rabbits with early-onset synostosis had significantly (p &lt; 0.05) more fluctuating asymmetry in the BL dimension compared to wild-type controls. Results demonstrate increased fluctuating dental asymmetry in rabbits with nonsyndromic, early-onset coronal suture synostosis and suggest that the molecular events producing suture synostosis locally may have also have systemic effects. Knowledge of these systemic interactions may contribute to a fuller understanding of the phenotypic spectrum observed in individuals with nonsyndromic craniosynostosis.

Mandibular and maxillary canine as a tool for sex determination

Abstract Introduction: Teeth measurement assist in the forensic and anthropological investigation to estimate age, confirm sex and race of a person. Maximum resistance to change in a natural disaster and also the most level of sexual dimorphism in canines makes them important in mentioned fields. Materials and Methods: During this study, an effort has been created to determine the sex of a person by using Canine Index (CI) which calculated for mandibular and maxillary canines. Mesio-distal (MD) breadth of canines and also the respective inter-canine distances (ICD) were tested using the independent samples t-test revealed significant sex dimorphism among the 100 individuals (50 males and 50 females) of Iranian population in the age group of 18-35 years. Conclusion: It is evident from our study that the maxillary canine index (MaxCI) is a valuable tool for determining sex.

A preliminary assessment of a new dedicated endodontic software for use with CBCT images to evaluate the canal complexity of mandibular molars.

To investigate invivo the complexity of canals within mesial roots of mandibular molars using 3D Endo™ software linked to CBCT images. The CBCT images of 100 mandibular first molars were analysed using the 3D Endo™ software. The number of canals in the mesial roots, the presence of apical confluences, the canal lengths and the canal configurations using Vertucci's classification were evaluated in buccolingual (BL) and mesiodistal (MD) views. The software allowed the visualization of canal trajectories in three dimensions using a coloured outline, which was used to develop a new objective scoring system to provide an overall assessment of canal complexity. Data were analysed statistically using anova and t-tests with the significance set at P<0.05. Vertucci type IV canals were found in 44% of the cases, whilst 54% were type II. The mean distance from the apical foramen to the orifice was 13.15mm (±1.21) and that between a confluence and the foramen, 2.81mm (±1.13). The number of curvatures and the canal complexity scores in the MD view were significantly higher than in the BL view (P<0.05). The scores were not directly correlated to the canal (MB versus ML), to the canal length or to the presence of confluences. 3D Endo software features the automatic detection and measurement of several anatomical canal parameters, and is a promising tool for the study of canal complexity invivo. The unpredictable anatomy of the mesial roots of mandibular molars highlights the value of a three-dimensional preoperative evaluation of each case. The proposed scoring system aims to provide the clinician with an overall assessment of canal complexity.

The Influence of Low Insertion Torque on Primary Stability, Implant Survival, and Maintenance of Marginal Bone Levels: A Closed-Cohort Prospective Study.

The purpose of this study was to evaluate the impact of low insertion torque on primary stability and the short-term clinical outcome of single-tooth implants placed into healed ridges and fresh extraction sockets. A cohort of n = 30 implants was self-selected on the basis that their insertion torque measured ≤ 20 Ncm. The cohort was closed with the follow-up set at 1 year. Resonance frequency analysis was evaluated in both mesiodistal (MD) and buccolingual (BL) directions at the time of implant insertion and at the time of restoration. Immediate temporization was determined by the esthetic need and a minimum implant stability quotient (ISQ) reading of 55. Implants were definitively restored after approximately 3 months. Implant survival was recorded along with changes in the level of the marginal bone relative to a fixed reference point, at the 1-year follow-up. Twenty-two patients with a total of 30 implants were grouped by insertion torques of < 5 Ncm (spinners), > 5 < 10 Ncm, 10 Ncm, 15 Ncm, and 20 Ncm. One implant was excluded because follow-up data were unavailable. Of the remaining 29 implants, the mean ISQ measured 67 (MD) and 65 (BL) at surgery. The values increased to 80 (MD) and 79 (BL) after a period of 3 months. The survival rate at the end of the 1-year period was 96.7%, including the excluded implant, but 100% for the remaining 29 implants. The frequency of implants demonstrating no marginal bone loss was 71.4%, 0.1 to 0.5 mm bone loss was 21.4%, and bone loss > 0.5 mm (max = 2.82 mm) was only 7.2%. No implants were lost during the functional loading period. Data on immediate temporization revealed no significant difference in ISQ or marginal bone loss values for implants in this group. Lower insertion torques yield favorable survival rates with optimal marginal bone levels compared with the accepted norm.

Convergence Angles of Clinical Tooth Preparations for Metal Ceramic Restorations Among Dental Students and General Practitioners

Background: Numerous studies showed that the convergence angle (CA) of prepared teeth for fixed prosthodontics in the clinical practice is greater than the recommended values. Objectives: This cross-sectional study aimed to compare the total occlusal convergence (TOC) angles of metal ceramic fixed prosthodontics among dental students [final-year undergraduate (UG) and Master Prosthodontics (MS) students] and general practitioners (GP) in their private clinics with the recommended value (≤ 12 degrees). Methods: The buccolingual (BL) and mesiodistal (MD) TOC of 114, 90, and 111 stone dies referred to UG, MS, and GP, respectively, were measured. These dies included incisors, premolars, and molars. One sample Wilcoxon signed rank test, Mann-Whitney U test, Kruskal-Wallis, and Fisher exact test were used for statistical analysis. Results: Mean values of TOC for UG were 27.8 degrees BL and 20.9 degrees MD, whereas they were 30.6 degrees BL and 18.2 degrees MD for MS. GP had TOC of 35.5 degrees BL and 24 degrees MD. GP had significantly higher TOC values than the other groups (0.001 > P value ≤ 0.007). In each group, TOC did not differ when calculated for partial fixed prosthodontic and single crown abutments (0.117 ≤ P value ≤ 0.797). Molars in general had the highest TOC values. Only 0.9%, 3.3%, and 0.9% of UG, MS, and GP, respectively, respected the TOC ≤ 12 degrees. Conclusions: In all the groups, tooth preparations were inconsistent with the recommended TOC values, even among specialists in fixed prosthodontics. These results support the existing literature that the recommended values were rarely achieved and may require reconsideration. Clinical Significance: Clinically, the CA values of prepared teeth for fixed prosthodontics exceed the recommended values in most cases, not only among general practitioners, but also among students in academic institutes. Thus, the effects of teeth preparations with CA greater than the recommended values on the longevity of the prosthodontics should be further investigated.

Dental occlusion analysis in the Mesolithic–Neolithic Age, Bronze Age, and Roman to Medieval times in Serbia: Tooth size comparison in skeletal samples

ObjectiveAnthropological studies have reported that tooth size decreases in the context of diet changes. Some investigations have found a reverse trend in tooth size from the prehistoric to the modern times. The aims of this study were to analyze tooth size in skeletal samples from Mesolithic–Neolithic Age, Bronze Age, and Roman to Medieval times to determine sex differences and establish a temporal trend in tooth size in the aforementioned periods. DesignWell-preserved permanent teeth were included in the investigation. The mesiodistal (MD) diameter of all teeth and buccolingual (BL) diameter of the molars were measured. Effects of sex and site were tested by one-way ANOVA, and the combined effect of these factors was analyzed by UNIANOVA. ResultsSexual dimorphism was present in the BL diameters of all molars and MD diameters of the upper first and the lower third molar. The lower canine was the most dimorphic tooth in the anterior region. The MD diameter of most teeth showed no significant difference between the groups, (sample from: Mesolithic–Neolithic Age-group 1; Bronze Age-group 2; Roman times-group 3; Medieval times-group 4), whereas the BL diameters of the upper second and the lower first molar were the largest in the first group. Multiple comparisons revealed a decrease in the BL diameter of the upper second and the lower first molar from the first to the later groups. Lower canine MD diameter exhibited an increase in the fourth group compared to the second group. ConclusionOn the basis of the MD diameter, a temporal trend could not be observed for most of the teeth. The lower canine exhibited an increase in the MD diameter from the prehistoric to the Medieval times. Changes of BL diameter were more homogeneous, suggesting that the temporal trend of molar size decreased from the Mesolithic–Neolithic to Medieval times in Serbia.

Subjective Differences between Dentists and Patients about Relative Quality of Metal Ceramic Restorations placed in the Esthetic Zone

Esthetic perceptions could differ between the dentist and his patients among various regions and cultures. The aims of this study were to evaluate the subjective differences between the dentist and the patient in terms of esthetics of metal-ceramic crowns (MCcs). The study also aims to compare the mesiodistal (MD) and buccolingual (BL) dimensions of the cemented crown with its respective natural antimeric tooth. A total of 85 patients seeking treatment for a single crown (MC) were treated by the undergraduate students under supervision of respective academic staff. After cementation of the crowns, a 9-point questionnaire was given to patient and different dentists. A treatment cast for every single crown was poured. Then, the MD and BL dimensions of the crowns were compared against their respective antimeric tooth. The dentists and the patients agreed in the range of 50.5 to 90.5%. Least subjective differences were found for the length and width of the cemented crowns. The highest differences were noted for symmetry between the cemented crown and its antimeric natural tooth. A total of 31 to 38% of the patients differed from the dentist's evaluation for shade of the crown, color of the crown at the margin, contour of the crown, and the relationship of the crowns with the surrounding gingiva. The highest MD and BL dimensions were in the cemented crown of canines, while the lowest MD and BL diameters were for the cemented crowns of the lateral incisor crowns. Dentist and patient mostly agreed in terms of length (90%), width (81%) and relation of crown with free gingiva (74%). However, they differed mostly on the symmetry of the cemented crowns. The highest MD dimensions and BL diameter were in the cemented MCcs of canine, while the lowest were with lateral incisors. While fabricating a dental prosthesis, the dentist must know about patients' perception of esthetics; otherwise both clinical and laboratory efforts would not be enough to satisfy the esthetic needs of the patient even if the restoration is technically correct. Perceptions related to symmetry differ mostly between dentist and patient.

Gender determination by odontometric method.

Context:Gender determination is central in establishing personal identification from human skeletal remains. The study was conducted to find out the accuracy with which gender can be determined by odontometric methods.Aims:To investigate the mesiodistal (MD) and buccolingual (BL) dimensions of all the teeth of permanent dentition to find new parameters to differentiate between male and female teeth and to assess whether each type of linear measurement can be used independently in odontometric sex differentiation.Materials and Methods:The study was conducted at a dental college on a composite group of 500 individuals comprising 250 males and 250 females. Impressions of upper and lower jaws were made with alginate impression material and casts prepared with dental stone. A digital Vernier calliper was used to measure the BL and MD dimensions of all the upper teeth except the third molars.Statistical Analysis Used:The results were subjected to statistical analysis using univariate analysis and linear stepwise discriminant function analysis to find the variables which discriminate gender significantly.Results:The MD and BL dimensions between males and females were statistically significant. The predicted value for correct classification of gender was also statistically significant.Conclusions:The ability to differentiate gender in the population using stepwise discriminant functions was found to be very high with 99.8% accuracy with males showing statistically larger teeth than females. This is similar to the near 100% success in gender determination using pelvic and skull bones.

Applicability of odontometric dimensions and indices in sexual dimorphism among Nalgonda population.

Background:Teeth morphology varies among different population groups as they are exposed to various environmental conditions. Teeth being the most stable and hard tissue, human identification can be made when the other tissues are unavailable. Odontometric analysis can be considered for anthropological and forensic investigations.Aim:The aim of this study is to assess the reliability of odontometric mesiodistal (MD) width dimensions and indices in sexual dimorphism among Nalgonda population.Materials and Methods:A total of 180 ideal study dental models of patients between the age range of 18 and 25 years were collected from the Department of Orthodontics. Selection criteria include teeth with Class I molar and canine relation, free of anomalies, or caries. Maximum MD widths of all teeth and arch parameters (intercanine width, interpremolar width, and intermolar width) were measured and incisor index, canine index, premolar index, and molar index were calculated. Sexual dimorphism was calculated using Garn and Lewis equation.Statistical Analysis:The recorded data were subjected to statistical analysis using independent unpaired t-test.Results and Conclusion:Mandibular canines followed by maxillary canines showed greater sexual dimorphism among all teeth. Maxillary right canine index, mandibular left canine index, maxillary right incisor index, inter premolar and intermolar widths showed statistically significant difference between males and females (P < 0.05). The results of this study revealed significant sexual dimorphism with the use of odontometric dimensions, canine index, incisor index, and arch parameters. These parameters could be used as adjunctive aids by the forensic expertise in human identification.

Mandibular canine index: A study for gender determination in Gandhinagar population.

Introduction:One of the important pieces of information gathered from tooth analysis is the sex of an individual. In most human living populations, mandibular canines show the greatest dimorphism and greatest dimensional differences between males and females. In view of these facts, the aim of this study was to establish the standard mandibular canine index (MCI) and estimate the sexual dimorphism in the population of Gandhinagar district of Gujarat state.Materials and Methods:The study consisted of 400 subjects, 200 males and 200 females in the age group of 20–40 years. The mesiodistal (MD) width of the right and left canine and the intercanine distance were measured. These values were used to derive the MCI and establish the amount of sexual dimorphism exhibited by the mandibular canine.Results:The MD crown width of the permanent mandibular right and left canines as well as mandibular intercanine distance of the males was found to be larger in size than in the females. The right mandibular canine exhibited 8.42% of sexual dimorphism while the left mandibular canine exhibited 8.40% of sexual dimorphism. The intercanine distance showed 2.75% of sexual dimorphism. The value of standard MCI derived using the formula devised by Rao et al. was 0.254 mm for the population residing in the Gandhinagar district.Conclusion:The present study supports the usefulness of the MCI in gender determination. The method of using mandibular canine indices is advantageous as it is easy, rapid, and cost-effective, requires no elaborate apparatus, and is suited for situations where large a number of samples have to be analyzed.

Effectiveness of hand and Mtwo™ instruments in preparing oval-shaped root canals: in vitro study

Objective: This study evaluated through stereomicroscopy the effectiveness of hand and rotary instrumentation techniques, either isolated or combined, in the preparation of oval-shaped root canals. Materials and method: Thirty single-rooted human mandibular incisors were selected. After endodontic access and coronal preflaring, teeth were mounted in a modified Bramante muffle and then sectioned transversely at 3 and 6 mm from the root apex. Images of each section were made under a stereomicroscope at 30× magnification. Teeth were reassembled in the muffle and divided into three groups (n=10) according to the root canal preparation technique: GI - rotary preparation with Mtwo™ basic sequence (10/.04; 15/.05; 20/.06; 25/.06), followed by Mtwo™ complementary instruments (30/.05; 35/.04; 40/.04); GII - rotary preparation with Mtwo™ basic sequence, complemented by hand instruments (#30, #35 and #40); GIII - hand instrumentation using the conventional technique (#10 to #40). All instruments were used in brushing motion. The muffles were separated again so that new images of each section could be obtained. The following parameters were evaluated in pre- and postoperative images: root canal area; perimeter; mesiodistal (MD) and buccolingual (BL) diameters; and mesial (M) and distal (D) wall thickness. Next, the values measured in post- and preoperative images were subtracted forcomparison of experimental groups. Data were analyzed using the Kruskal-Wallis test (α=0.05). Results: No significant difference between groups was observed for all parameters. Conclusion: There was no difference among hand, rotary, or combined instrumentation; all techniques were able to increase root canal area, perimeter, and diameter in MD and BL directions. Moreover, the amount of dentin wearon proximal root canal walls was similar for all tested groups.

Odontometric analysis of molars for sex determination

Aim: To investigate the existence of sexual dimorphism between the first and second permanent molars. Methods: A cross-sectional, observational, blind study using comparative and statistical descriptive procedures. The sample included 50 pairs of plaster casts from undergraduate dental students (25 men/25 women) from the Federal University of Paraíba, João Pessoa/PB, Brazil, aged 20-26 years. Odontometric measurements of first and second maxillary/mandibular, right/left permanent molars were performed. Mesiodistal (MD) and buccolingual/palatal (BL/BP) widths and the distance between the lingual cusps of corresponding molars in opposite quadrants, were measured. The data were analyzed by Student’s t test and ANOVA with Bonferroni (p≤0.05). Results: The crowns of all first molars were statistically larger in men than in women (p&lt;0.05). Maxillary and mandibular left second molars (#27 and #37) did not differ in their MD widths (p=0.66, p=0.75), whereas mandibular left and right second molars (#37 and #47) showed statistically different BL widths (p=0.007 and p=0.008). As to the distance between the lingual cusps, only the first left-to-right mandibular molars (#36-46) showed no sex dimorphism (p=0.107). Conclusions: Molars are larger in males than in females. Individually, first molars demonstrated higher evidence of sex distinction than second molars.

Complex systems in human development: sexual dimorphism in teeth and fingerprints of Australian twins

Human teeth and fingerprints have similar embryological origin from epithelial-mesenchymal interactions. This study aims to determine the nature and extent of sexual dimorphism in fingerprints and teeth of twins; investigate the influences of genetic, epigenetic and environmental factors on observed variation; identify possible developmental associations between the phenotypes; and explore whether both systems display the features of complex adaptive systems. Mesiodistal (MD) measurements from both primary and permanent teeth and ridge density (RD) from three different finger areas, namely ulnar (U), radial (R), and proximal (P), from fingerprints of the same set of monozygotic and dizygotic Australian twins (28 males and 31 females aged 8 to 10 years, and aged 13 to 16 years, respectively) were collected and analysed. Sexual dimorphism was observed in both the primary and permanent dentitions, with the latter showing greater magnitude of differences than the former. There was no observed sexual dimorphism in the fingerprints of the 8 to 10 year cohort, but a few finger areas (left index U, right index R, left little R, and left little P) of the 13- to 16-year cohort exhibited significant differences, showing that friction ridges expand over time. It was concluded that both dentition and dermatoglyphics display characteristics of complex adaptive systems.