Dental arch dimensions in the mixed dentition: a study of Brazilian children from 9 to 12 years of age

The association between dental and dentoalveolar arch forms of children with normal occlusion and malocclusion: a cross-sectional study

BACKGROUND

Symmetrical and coordinated dental and alveolar arches are crucial for achieving proper occlusion. This study aimed to explore the association between dental and dentoalveolar arch forms in children with both normal occlusion and malocclusion.

METHODS

209 normal occlusion subjects (5-13 years, mean 8.48 years) and 199 malocclusion subjects (5-12 years, mean 8.19 years) were included. The dentoalveolar arch form was characterized by the smoothest projected curve representing the layered contour of the buccal alveolar bone, referred to as the LiLo curve. Subsequently, a polynomial function was utilized to assess dental and dentoalveolar arch forms. To facilitate separate analyses of shape (depth/width ratio) and size (depth and width), the widths of dental and dentoalveolar arch forms were normalized. The normalized dental and dentoalveolar arch forms (shapes) were further classified into 6 groups, termed dental/dentoalveolar arch clusters, using the k-means algorithm.

RESULTS

The association between dental and dentoalveolar arch clusters was found to be one-to-many rather than one-to-one. The mismatch between dental and dentoalveolar arch forms is common in malocclusion, affecting 11.4% of the maxilla and 9.2% of the mandible, respectively.

CONCLUSIONS

There are large individual variations in the association between dental and dentoalveolar arch forms. Early orthodontic treatment may play an active role in coordinating the relationship between the dental and dentoalveolar arch forms.

Computer-Guided Evaluation of the Use of Two Different Devices in the Reduction of Inferior Tooth Crowding

OBJECTIVE

Lower tooth crowding is considered one of the most common malocclusions in growing patients and due to the potential complications associated with it, it is recommended to intercept this condition as soon as possible. The purpose of this paper is to examine and compare the effectiveness of two different orthodontic devices (elastodontic device and clear aligners) in the treatment of anterior tooth crowding in the jaws of young patients.

MATERIALS AND METHODS

Seventy patients aged between 10 and 16 years with anterior inferior tooth crowding were recruited into this study and divided into case and control groups. The former group comprised 35 patients (15 males and 20 females, average age 10.2 years) who were treated with elastodontic devices (EQ CP series, Eptamed), while the control group consisted of 35 patients (15 males and 20 females, average age 10.5 years) who received aligners (Invisalign). All patients underwent periodic visits after 6 months from the start of treatment (T1) and after 1 year (T2) in which the progress of therapy was evaluated by measuring the inferior intercanine distance using a digital caliper. A parametric ANOVA test was conducted for statistical analysis.

RESULTS

There is no statistically significant difference between the two groups at either T1 or T2 (p < 0.05), thus making the two treatment modalities comparable.

CONCLUSIONS

Both elastodontic devices and aligners can be considered as effective tools to successfully conduct inferior expansive treatment for the resolution of tooth crowding; however, the elastodontic devices are considered more comfortable to wear and they are required to be worn for less time during the day.

A Comparative Analysis of Arch Widths in Class I and Class II Malocclusion: Extraction vs. Non-extraction Treatment

INTRODUCTION

This study aimed to assess and compare dental arch widths in the anterior and posterior regions among patients undergoing extraction and non-extraction treatments for Class I and Class II malocclusions.

MATERIALS AND METHODOLOGY

A total of 40 patients were selected, with 10 in each of the categorized groups based on malocclusion type and treatment status. Dental arch widths were meticulously measured using a digital Vernier caliper at the canine and molar regions to ensure precise data collection.

RESULTS

Statistically significant differences were noted when comparing mean inter-canine and molar widths between pre- and post-treatment periods among extraction cases in Class I malocclusion (p < 0.001). Conversely, there were no significant changes observed in arch widths among non-extraction cases in Class I malocclusion. Similarly, significant changes were observed in both extraction and non-extraction cases of Class II malocclusion when comparing mean inter-canine and molar widths between pre- and post-treatment periods (p < 0.05).

CONCLUSION

After treatment, both Class I and Class II extraction cases showed an increase in inter-canine arch width, while intermolar arch width remained unchanged, suggesting that the treatment did not significantly alter the buccal corridor. Additionally, there were no notable changes in inter-canine arch widths between pre- and post-treatment in Class I non-extraction cases. However, the Class II non-extraction group exhibited increased upper and lower inter-canine arch widths after treatment.

Comparative evaluation of arch form among the Nepalese population: A morphological study

Aims

The study aims to identify sexual dimorphic features in the arch patterns based on tooth arrangement patterns and the maxillary and mandibular arches using Euclidean Distance Matrix Analysis (EDMA).

Settings and Design

A total of 96 Nepalese subjects, aged 18 to 25 were assessed using casts and photographs.

Materials and Methods

Thirteen landmarks representing the most facial portions of the proximal contact areas on the maxillary and mandibular casts were digitised. Seventy-eight possible, Euclidean distances between the 13 landmarks were calculated using the Analysis ToolPak of Microsoft Excel®. The male-to-female ratios of the corresponding distances were computed and ratios were compared to evaluate the arch form for variation in the genders, among the Nepalese population.

Statistical Analysis Used

Microsoft Excel Analysis ToolPak and SPSS 20.0 (IBM Chicago) were used to perform EDMA and an independent t-test to compare the significant differences between the two genders.

Results

The maxillary arch's largest ratio (1.008179001) was discovered near the location of the right and left lateral incisors, indicating that the anterior region may have experienced the greatest change. The posterior-molar region is where the smallest ratio was discovered, suggesting less variation. At the intercanine region, female arches were wider than male ones; however, at the interpremolar and intermolar sections, they were similar in width. Females' maxillary arches were discovered to be bigger antero-posteriorly than those of males. The highest ratio (1.014336113) in the mandibular arch was discovered at the intermolar area, suggesting that males had a larger mandibular posterior arch morphology. At the intercanine area, the breadth of the arch form was greater in males and nearly the same in females at the interpremolar and intermolar regions. Female mandibular arch forms were also discovered to be longer than those of males from the anterior to the posterior.

Conclusions

The male and female arches in the Nepalese population were inferred to be different in size and shape. With references to the landmarks demonstrating such a shift, the EDMA established objectively the presence of square arch forms in Nepali males and tapering arch forms in Nepalese females.

Longitudinal behavior of orthodontic extraction spaces: A retrospective dental cast analysis

INTRODUCTION

This retrospective study aimed to qualitatively and quantitatively evaluate orthodontic extraction space behavior and size at the end of treatment and the short- and long-term stages in Class I, II, and III malocclusions.

METHODS

The sample comprised records of 1283 orthodontic patients treated with extractions (cross-sectional group). From these patients, 1- and 5-year posttreatment records of 214 patients were additionally evaluated (longitudinal group). Orthodontic extraction sites of immediate (end of treatment), short-term (1-year posttreatment), and long-term (5-year posttreatment) stage dental casts were measured with a digital caliper. Extraction spaces were classified according to their qualitative behavior in the open, closed, reopened, and recently closed spaces. Space qualitative longitudinal behavior was compared among the malocclusion types with chi-square tests. Kolmogorov-Smirnov normality tests were performed to check the variable's distribution. All variables showed normal distribution, except the malocclusion group ages. Therefore, parametric tests were used for all comparisons between the malocclusion groups, except for age comparisons in each stage, which were compared with the Kruskal-Wallis tests. Thus, space size and its reduction were compared among the 3 stages, in general, and between the maxillary and mandibular arches, with analysis of variance followed by Tukey tests and t tests, respectively.

RESULTS

Classes I, II, and III malocclusion patients presented similar ages at each stage. At the end of treatment, 71.4% and 65.1% of the quadrants were closed in the cross-sectional and longitudinal groups, respectively, and 43.6% and 38.2% of patients presented all quadrants closed at this same stage in both groups. The reopening and late closure tendencies were 2.9 and 2.3 times greater in the short term than in the long term. Reopening tendency in the short-term was greater in Class II than in Class I malocclusion. Of the quadrants closed at the end of treatment, 87% were stable in the long term. From the quadrants with residual spaces at the end of treatment, 28.4% persisted openly in the long term. Residual space size reduced significantly in the short and long term, primarily in the mandibular arch.

CONCLUSIONS

The percentage of patients with residual spaces at the end of treatment was 56.4%. Space reopening and late closure occur mainly in the first year after treatment. There was long-term stability in 87% of the quadrants closed at the end of treatment. There was a significant reduction in orthodontic extraction space size in the short and long term, especially in the mandibular arch.

Comparative Evaluation of Occlusal Bite Force in Relation to the Muscle Activity in the Mixed Dentition Children of Age Group 9-12 Years: A T-scan Analysis

Aim and objective

Compare and evaluate the muscle activity and the occlusal force between the mixed dentition boys and girls of 9-12 years.

Materials and methods

The study included 15 boys and 15 girls. The occlusal force and activity of the masseter and temporalis muscle were measured with a T-scan device using a sensor, a module to transmit the signals to a computer and the complete data of the bite force and muscle activity with the EMG recordings and data were collected and evaluated.

Results

Relative occlusal force in the primary and permanent molars between the boys and girls showed no significant difference on the left side compared to the right. The electromyography values of masseter and temporalis in boys and girls showed a significant difference in which (TAR and MMR), (TAR and MML), (TAL and MMR), and (TAL and MML) are significant. The overall paired sample statistics showed higher muscle activity in masseter.

Conclusion

T-scan analysis has proved to be a dependable method for the evaluation of occlusal bite force with the muscle activity interpretation using EMG. This study concluded that there is a difference in the occlusal pattern and muscle activity in the mixed dentition that showed the maximum force was on the permanent molars and the symmetry of EMGs activity in children was on the right masseter comparatively with higher bite values in boys compared to girls.

Clinical significance

T-scan is a computerized analysis system that helps in the proper assessment of the patient's occlusion and assists in the proper treatment planning and diagnosis accurately without much effort.

How to cite this article

Prabahar T, Gupta N, Chowdhary NR, et al. Comparative Evaluation of Occlusal Bite Force in Relation to the Muscle Activity in the Mixed Dentition Children of Age Group 9-12 Years: A T-scan Analysis. Int J Clin Pediatr Dent 2021;14(S-1):S29-S34.

Estimation of the Intercanine Width, Intermolar Width, Arch Length, and Arch Perimeter and Its Comparison in 12-17-year-old Children of Faridabad

Context

Dental arch morphology is an important consideration in the orthodontic treatment of dentofacial deformities. The size and shape of the arches have considerable implications in treatment planning, affecting space available, dental esthetics, and stability of dentition. The data provided by this study will be of considerable importance and relevance for practicing orthodontists and pedodontists in the region of Faridabad

Aim and objective

This study aims to determine and compare the intercanine width, intermolar width, arch length, and arch perimeter in the early adolescent group (12–14 years) and middle adolescent group (15–17 years) of Faridabad.

Materials and methods

Maxillary and mandibular impressions were made, study casts were prepared then the measurement of the individual intercanine widths, intermolar widths, arch length of maxillary and mandibular casts with the digital caliper, and arch perimeter with the help of brass wire was taken, obtained values were calculated, hence the results were evaluated.

Statistical analysis

Data were entered into a Microsoft Excel spreadsheet. It was analyzed using Statistical Package for Social Sciences (SPSS) version 21. Graphs were prepared using Microsoft Excel. Data were normally distributed as tested using the Shapiro-Wilk W test (p value was <0.05). Inferential statistics were performed using independent Student's t-test. The level of significance was set at 0.05.

Results

In the present study, all the parameters measured were increased in males in both the age-groups, i.e., the early adolescent group (12–14 years) and the mid adolescent group (15–17 years), and a significant increase was seen in the intercanine and intermolar widths in males.

How to cite this article

Singh S, Saraf BG, Indushekhar KR, et al. Estimation of the Intercanine Width, Intermolar Width, Arch Length, and Arch Perimeter and Its Comparison in 12–17-year-old Children of Faridabad. Int J Clin Pediatr Dent 2021;14(3):369–375.

Reference parameters for normality and associated factors to hard palate during mixed dentition phase

PURPOSE

To evaluate the association among dimensions of the hard palate according to the sexes, skin color, and periods of the mixed dentition and present reference parameters of normality for this stage of development.

METHODS

This cross-sectional study evaluated a representative sample of children between the ages of 7 and 13 years in Santa Maria, southern Brazil. The outcomes of the study were the dimensions of the palate: width measurements and depth. Sociodemographic characteristics and related oral measures were also assessed. Adjusted linear regression model were used to evaluate the effect of the predictor's variables on the dimensions of the hard palate in millimeters. The reference standards for the hard palate normality were presented in mean, standard deviation, and 95% confidence interval.

RESULTS

A total of 569 children were evaluated. The hard palate dimensions were larger in the male sex and smaller in the first transitional period of mixed dentition. Skin color had an influence on the hard palate width at the level of the premolars, and the width measurements were smaller in white individuals. Posterior cross bite, Angle Class II and III malocclusions and non-nutritional sucking habits caused reduction in the hard palate width measurements.

CONCLUSION

Different dimensions of the hard palate are influenced by demographic variables such as sex, skin color, and mixed dentition period. Children of the female sex, white-skinned and in the first transition period of mixed dentition had smaller dimensions of the hard palate. Establishing normality reference standards in measurements of the palates guides the clinical practice.

Dental changes in humans with untreated normal occlusion throughout lifetime: A systematic scoping review

INTRODUCTION

Understanding age-related changes in normal dental occlusion is crucial for orthodontic treatment, planning, and retention, especially considering the increasing demand from adult patients. This review aimed to systematically perform a scoping literature review regarding age-related dental changes in untreated normal occlusion subjects.

METHODS

An electronic search was performed until May 2020 using the following terms: "Dental Occlusion," "Dentition," "Ageing," and "Age groups." Articles studying changes in dental occlusal traits in orthodontically untreated subjects with neutroclusion and comparing them between various age groups were included. Studies focusing on a single age group or written in languages other than English were excluded. The risk of bias of the studies was assessed with both the methodological index for nonrandomized studies and the risk of bias in nonrandomized studies of intervention tools.

RESULTS

From the initial 7681 articles, 40 were included. High methodologic heterogeneity was found among studies. Intercanine width was found to increase until 8.0 years and 15.0 years in the mandible and maxilla, respectively, whereas intermolar width increases in both arches until 26.0 years. After that, both parameters decrease into late adulthood. Crowding increases from mixed dentition until 60.0 years of age, especially in the mandible and females. Maxillary incisors procline with age while mandibular incisors retroclined.

CONCLUSIONS

The age-related evolution of occlusal traits, together with skeletal and soft tissue changes, should be considered during orthodontic planning. Well-designed prospective cohort studies are necessary for confirmatory evidence. Expectations for treatment stability should consider muscular balance and inform patients that crowding is a sign of aging that should not always be seen as a failure of orthodontic therapy. Protocol registration number: PROSPERO CRD42020138846.

Cleaning the palate and tongue without nausea: a mixed methods study exploring the appropriate depth and direction of oral care

BACKGROUND

It is advisable to clean the palate and tongue thoroughly during oral care to protect against nosocomial infections. However, improper cleaning may cause nausea. To date, no robust data are available regarding how to implement this procedure properly. Furthermore, traditional cotton balls, forceps and normal saline are still used in clinical in China. This mixed methods study aimed to explore the appropriate depth and direction of cleaning methods for palates and tongues without causing nausea and the factors influencing cleaning depth and discomfort in traditional oral care.

METHODS

Our study recruited students (n = 276) from a medical university. The first phase was a quantitative study, in which forceps were slowly inserted into their throats until the gag reflex was triggered, and then, the insertion depth was measured. After that, participants were randomly divided into two groups. In group A, palates and tongues were cleaned coronally and then sagittally, with the converse order used for group B. The extent of nausea was measured. Additionally, the qualitative data were types of discomfort other than nausea reported by the participants.

RESULTS

The tolerable depths (without causing nausea) for cleaning the palate and tongue were 6.75 ± 1.07 cm and 6.92 ± 1.11 cm, respectively. Participants of male sex and with high BMI (overweight/obese) were associated with greater tolerable cleaning depth. The extent of nausea caused by cleaning both the palate and the tongue sagittally was higher than that elicited by coronal cleaning (p = 0.025 and p = 0.003, respectively). Other discomforts included itching, saltiness and coldness.

CONCLUSION

It is appropriate to increase the cleaning depth of the palate and tongue for adult males and overweight/obese individuals. Moreover, coronal cleaning causes lower levels of nausea, and traditional oral care appliances should be improved.

Brain Cortex Activity in Children With Anterior Open Bite: A Pilot Study

Anterior open bite (AOB) is related to functional alterations of the stomatognathic system. There are no studies concerning brain activation of the cortex comparing children with and without AOB during rest and activities such as deglutition and phonation. The aim of this study was to determine the activity of the brain cortex of children with AOB at rest and during phonation and deglutition and to evaluate the association of intelligence quotient (IQ), attention (Test of Variables of Attention, known as TOVA), beats per minute (BPM), and oxygen saturation measurement (SpO₂) with brain activity in subjects with AOB. Fourteen children (seven with AOB and seven without AOB) with mixed dentition, aged 10–13 years, underwent an IQ test, TOVA, SpO₂, and quantitative electroencephalography (QEEG). Electrodes were set in the scalp, according to the 10–20 protocol. Data were analyzed using statistical tests to assess comparisons between children with and without AOB. The results showed that IQ, TOVA, SpO₂, or BPM did not show any statistically significant differences between the groups, except for the response time (contained in TOVA) (p = 0.03). Significant differences were found for the brain activity during rest (Condition 1) of the tongue, between children with and without AOB (p < 0.05 for alpha/theta and alpha peaks), whereas there were no differences during function (Condition 2). The findings of this investigation provide insights about the cortex activity of the brain while the tongue is in the resting position in children with AOB. This may imply an altered activity of the brain cortex, which should be considered when diagnosing and treating AOB. Other diagnostic techniques derived from investigations based on neuroscience could develop new diagnostic and therapeutic techniques to give better solutions to children with malocclusions. Treatments should be focused not only on the teeth but also on the brain cortex.

Relationship between oral function and mandibular anterior crowding in early mixed dentition

The position of the dentition is considered to be determined by a combination of forces exerted by the perioral muscles and tongue. We hypothesized that mandibular anterior crowding may be related to abnormalities in the development of oral function. To determine the relationship between oral function and mandibular anterior crowding in early mixed dentition. A total of 61 children (30 boys, 31 girls) with early mixed dentition were included in this study. Height, body weight, maximum occlusal force, lip‐closing strength, and maximum tongue pressure were measured in all participants, and their dental casts and lateral cephalograms were evaluated. Little's irregularity index (LII), evaluated by dental casts, was used as an indicator of mandibular anterior crowding. Maximum occlusal force and lip‐closing strength were not significantly correlated with the LII, although they were positively correlated with maximum tongue pressure, mandibular intercanine perimeter distance, and upper central incisor (U1)‐to‐NL angle (p < .05). Maximum tongue pressure was negatively correlated with LII (p < .05). Maximum tongue pressure and LII were significantly positively correlated with the mandibular intercanine perimeter distance and U1/NL angle, and negatively correlated with the interincisal angle (p < .05 for all). Crowding of the mandibular anterior teeth was directly correlated with tongue pressure function and indirectly correlated with maximum occlusal force and lip‐closing strength.

Comparing the Arch Forms between Mongoloid Race and Dravidian Race in 11-14-year-old Children

Aim and objective

To compare arch forms between Mongoloid race and Dravidian race in 11–14-year-old children.

Materials and methods

Total 10 subjects from each study group were selected. Impression of both maxillary and mandibular arches were taken of all the subjects. Dental casts were poured. Intercanine measurement can be termed as the distance across two canine cusp tips, and intermolar measurement can be termed as the distance across two mesiobuccal cusp tips. This distance was recorded for maxillary and mandibular casts by making use of digital Vernier caliper. Data were tabulated.

Statistical analysis

To note the statistical impact, a Chi-square test was applied.

Results

The difference across the two groups was found to be statistically significantly noteworthy (independent t test p < 0.001).

Conclusion

Group I (Mongoloid race) showed significantly larger intercanine to intermolar width compared to Dravidian race with wide flaring arches.

Clinical significance

The size and forms of dental arches exhibit considerable variability within and among human groups. This research demonstrated that while considering Mongoloid patients, we must make use of prior formed orthodontic wires for ovoid shaped arches in a trivial fraction of patients.

How to cite this article

Smitha S, Nagar P, Abinaya R, et al. Comparing the Arch Forms between Mongoloid Race and Dravidian Race in 11–14-year-old Children. Int J Clin Pediatr Dent 2020;13(S-1):S26–S28.

Evaluation of Growth and Development of Late Mixed Dentition Upper Dental Arch with Normal Occlusion Using 3-Dimensional Digital Models

Objective

The purpose of this study was to observe the three-dimensional growth and development of the maxillary arch in 10-year-olds with normal occlusion during the late mixed dentition stage.

Methods

Forty-four 10-year-old students (22 males and 22 females) who had normal occlusion during late mixed dentition were selected from an elementary school in Beijing, China. Once per year for three consecutive years, a dental cast was obtained from each subject, and the cast was scanned with a 3D digital scanner (R700 3D). The three-dimensional measurements of the maxillary dental arch and the inclination of the bilateral maxillary first molars were obtained from the digital model.

Results

The upper anterior arch length (UAAL), upper total arch length (UTAL), upper inter primary or permanent canine width (UICW), upper intermolar width (UIMW), and upper dental arch length (UDAL) increased by 0.959 mm, 0.583 mm, 0.955 mm, 1.462 mm, and 2.46 mm, respectively, over the two years (P < 0.001). UR6BL and UL6BL decreased by 4.416° and 7.133°, respectively, over the two years (P < 0.001). The values of the UICW and UIMW were 1.67 mm and 1.86 mm, respectively, larger in males than in females at 12 years old (P < 0.01). The change in the UTAL was 0.431 mm greater in males than in females over the 2 years (P < 0.05).

Conclusion

The UAAL, UTAL, UICW, UIMW, and UDAL in 10- to 12-year-olds with normal occlusion increased with age. The buccolingual inclination of the bilateral maxillary first molars inclined to the palatal side with age. The UICW and UIMW were larger in males than in females at 12 years old. The male UTAL increased more than the female UTAL over the 2 years.

Maxillary arch dimensions in the first 6 months of life and their relationship with pacifier use

PURPOSE

This study evaluated the maxillary arch dimensions at birth and 6 months of life, and to verify the influence of pacifier use on palatal development.

METHODS

Maxillary arch impressions were taken from 80 full-term newborns, appropriate for gestational age, from 24 to 72 h of life, and repeated after 6 months. Anatomical references were mapped on dental casts and measurements were taken. Parents were questioned about feeding practices and sucking habits. Data were analysed by Kruskal-Wallis test and hierarchical mixed regression model (p < 0.05).

RESULTS

Anterior maxillary segment (median [interquartile range]) presented an increase in transverse (Δ% = 81.90 [74.40-89.70]) and in length (Δ% = 76.20 [49.10-102.70]) relative growth. No differences were detected in palatine depth from birth (11.00 mm [10.30-11.70]) to 6 months (12.60 mm [12.0-13.90]).

CONCLUSIONS

Pacifier use was positively related to the increase in anterior segment length. In the first 6 months of life, the greatest relative growth of the maxillary arch occurs in the anterior region, showing this growth does not occur homogeneously. The use of pacifiers came to influence this process, even before the eruption of the upper incisors.

Evaluation of dental arch dimensions in 12 year-old Vietnamese children - A cross-sectional study of 4565 subjects

This study aimed to define the width and length of the dental arch in 12-year-old Vietnamese children, and to elucidate differences between genders and among ethnic groups. A cross-sectional study was conducted in 4565 12 years-old children from the 4 major ethnic groups in Vietnam (Kinh, Muong, Thai, and Tay), with a healthy and full set of 28 permanent teeth that had never had any orthodontic treatment and with no reconstructive materials at the measured points. The mean variables in all subjects were 36.39 mm for upper inter-canine width; 46.88 mm for upper inter-first molar width; 59.43 mm for upper inter-second molar width; 10.41 mm for upper anterior length; 32.15 mm for upper posterior length 1; 45.52 mm for upper posterior length 2; 28.31 mm for lower inter-canine width; 41.63 mm for lower inter-first molar width; 54.57 mm for lower inter-second molar width (LM2W); 7.06 mm for lower anterior length (LAL); 26.87 mm for lower posterior length 1 (LP1L); and 41.29 mm for lower posterior length 2. Significant differences in these parameters between genders were found in all ethnic groups, except for LAL in the Kinh and Thai groups, and LP1L in the Tay group. Significant ethnic differences were also found in almost all parameters except LM2W in both males and females. Taken together, the representative sizes of dental arches of 12-year-old Vietnamese children have been defined. Our data indicate that there are some variations in dental arch dimensions among ethnic groups and between genders.

Morphometric Study of the Hard Palate and Its Relevance to Dental and Forensic Sciences

This study was conducted to identify the morphometric features of the hard palate and to test the reliability of using palatal morphology in sex determination. Three hundred maxillary casts were collected from dental clinics in north Jordan. The age and gender of the patient and the serial number for each cast were recorded. The age range was 6 to 50 years old. A caliper was used to perform the following measurements: the length, width, and depth of the hard palate. In addition, the size, shape, and position of the incisive papilla were also determined. All measurements were done by a trained examiner who was able to perform the measurements in a reproducible manner. Statistical analysis showed that the mean palatal length, width, and depth, and size of dental papilla in both groups were the highest in males. The full logistic regression model including all the three predictors (length, width, and depth) indicated that the three parameters were significantly correlated with gender in the adult group. However, in the child group, only width and length were significantly (p=0.001, p > 0.042 respectively) correlated with gender. Regarding the shape and size of the incisive papilla, they were significantly different between males and females in both adult (p > 0.03) and child (p=0.001) groups. These findings might be potentially relevant to anthropological studies aiming at individual and/or sex identification. Moreover, the results might have clinical value in prosthodontics, especially in fabricating complete maxillary dentures for edentulous patients.

Do gender and age influence hard palate dimensions? A systematic review

PURPOSE

Analyze the influence of gender and age on hard palate dimensions and verify the reference parameters available in the literature.

RESEARCH STRATEGIES

Two reviewers independently performed a search at the Cochrane Library, PubMed-Medline and Web of Knowledge databases using descriptors according to the syntax rules of each database.

SELECTION CRITERIA

Observational or experimental human studies evaluating the dimensions of the hard palate or maxillary dental arch, with at least one transverse, vertical or sagittal plane measurement, in normal occlusions or class I malocclusions, and comparisons of the dimensions between genders and/or ages.

DATA ANALYSIS

Descriptive analysis with the following subdivisions: design, sample, evaluation instruments, measurements in millimeters, and statistical analysis. Quality of the included studies was verified by the Newcastle - Ottawa Quality scale.

RESULTS

Eighteen studies were selected and 11 presented results for hard palate or maxillary dental arch dimensions according to gender, six in age and gender and one in age only.

CONCLUSION

The dimensions were larger in males and progressive increase in the measurements was observed from birth to the permanent dentition period.

Palatal dimensions at different stages of dentition in 5 to 18-year-old Iranian children and adolescent with normal occlusion

BACKGROUND

This study was purposed to evaluate palatal width, height, and height index at various stages of dentition in Iranian children and adolescent with normal occlusion.

METHODS

This cross-sectional study was conducted on a random sample of 237 children (45% male and 55% female, aged 5-18 years) with normal occlusion selected from kindergartens and elementary and high schools in Hamadan, Iran. The subjects were clinically examined and classified based on dentition to primary (21.5%), mixed (21.9%), and permanent (56.5%) stages. Dental casts were obtained from all subjects. Palatal width (inter-molar and -canine distances), and height (at molar and canine areas) were measured on the casts by Korkhaus' compass and digital caliper. Palatal height index was calculated for each dentition stage. Data were analyzed by SPSS 15 using one-way ANOVA followed by Tukey's post hoc test and t- test (p <  0.05).

RESULTS

Palatal inter-molar and -canine width values were increased from primary to permanent dentition. Palatal height and palatal height index in mixed dentition were significantly lower than those in primary and permanent dentition. Palatal width at inter-molar and -canine distances was significantly higher in males than females. There was no significant difference in palatal height and palatal height index at molar area between males and females. However, palatal height and palatal height index at canine area were significantly higher in males compared to females.

CONCLUSION

These findings showed that palatal width increased from primary to permanent stage. Palatal height and palatal height index decrease from primary to mixed dentation, then increase from mixed to permanent dentition.

Evaluation of sexual dimorphism in arch depth and palatal depth in 500 young adults of Marathwada region, India

Context:

In exhibiting gender dimorphism, the bony pelvis and skull give the most reliable results from morphometric analysis. Palatal dimensions were reported to exhibit racial difference and sexual dimorphism in several studies.

Aim:

The aim of the present study was to measure the maxillary arch depth and palatal depth in Indian population to assess their use as a tool for sexual dimorphism.

Materials and Methods:

Two hundred and fifty males and 250 females in the age group of 17–25 years were enrolled in the study, and impressions of maxillary arch were made. Measurement of palatal depth and maxillary arch depth was carried out at specific reference points using Korkhaus compass and digital caliper, respectively. The comparison of maxillary arch depth and palatal depth values was done using independent t-test. P < 0.05 was considered statistically significant. Diagnostic performance of significantly different variable was quantified by plotting “receiver operating characteristic” (ROC) curve.

Results:

Arch depth mean values were significantly higher in males than females. However, palatal depth mean values, though higher in males, were not significant. Area under the curve in ROC curve for maxillary arch depth was found to be 0.76, indicating sufficiency of discriminatory power of this variable.

Conclusion:

The present study showed that maxillary arch depth can be used as a tool for sex determination along with other morphometric methods. Mean value of both maxillary arch depth and palatal depth can be used as the baseline value for given population to be used as a reference for further studies.

Buccolingual angulation and intermolar width changes in the maxillary first molars of untreated growing children

INTRODUCTION

Buccolingual inclinations of the maxillary permanent molars and intermolar widths increase with growth for Class I subjects. Changes for untreated Class II subjects have not yet been assessed. The aim of this study was to test the hypothesis that changes in palatal inclination of the maxillary molars and intermolar width throughout growth vary between Class I and Class II molar occlusions.

METHODS

Patients were selected from the Forsyth/Moorrees Twin Study. Dental models taken for 6 consecutive years of 55 untreated subjects (28 with Angle Class I and 27 with Angle Class II occlusion) were scanned. The images were superimposed on the palatal rugae, and the angle between a reference plane and the buccolingual inclination plane was used to calculate the buccolingual molar inclination at each time point. The distance between lingual groove points was used to calculate the intermolar width.

RESULTS

All molars showed increasing palatal inclinations over the 6 years. The change for each time interval was statistically significant. Class I subjects demonstrated significantly greater palatal inclination at each time point. The molar inclination changed by means of 4.99° for Class I subjects and 6.25° for Class II subjects. Intermolar width increased continuously (P <0.001) and was significantly greater (P <0.05) for Class I patients.

CONCLUSIONS

These results suggest that palatal inclination of the maxillary permanent first molars occurs continuously between ages 9 and 14 years, with Class II subjects showing greater changes. The intermolar width increases steadily during this time, with Class II subjects having a narrower intermolar width and less change over time.

Automatic gender determination from 3D digital maxillary tooth plaster models based on the random forest algorithm and discrete cosine transform

BACKGROUND AND OBJECTIVE

One of the first stages in the identification of an individual is gender determination. Through gender determination, the search spectrum can be reduced. In disasters such as accidents or fires, which can render identification somewhat difficult, durable teeth are an important source for identification. This study proposes a smart system that can automatically determine gender using 3D digital maxillary tooth plaster models.

METHODS

The study group was composed of 40 Turkish individuals (20 female, 20 male) between the ages of 21 and 24. Using the iterative closest point (ICP) algorithm, tooth models were aligned, and after the segmentation process, models were transformed into depth images. The local discrete cosine transform (DCT) was used in the process of feature extraction, and the random forest (RF) algorithm was used for the process of classification.

RESULTS

Classification was performed using 30 different seeds for random generator values and 10-fold cross-validation. A value of 85.166% was obtained for average classification accuracy (CA) and a value of 91.75% for the area under the ROC curve (AUC).

CONCLUSIONS

A multi-disciplinary study is performed here that includes computer sciences, medicine and dentistry. A smart system is proposed for the determination of gender from 3D digital models of maxillary tooth plaster models. This study has the capacity to extend the field of gender determination from teeth.

Computer-guided technique evaluation of the bony palate for planning individual implant placement

OBJECTIVE

Different clinical problems may require a surgical approach to the dental arch, such as dentofacial orthopedics, implant-supported dental prothesis, maxillary orthodontics protraction, removable appliances, and posttraumatic dental reconstruction. The aim of this study is to analyze the dental arch size and type for supporting individual dental protheses.

MATERIALS AND METHODS

In this study, the reference measurements on the length of the bony palate, maxillary intercanine width, maxillary intermolar width, and the ratio of the maxillary to the palatinal surface were studied in 120 bony palates using a computer software program.

RESULTS

The average length of the bony palate, maxilla, and palatine was measured as 104.4 ± 30.3, 40.05 ± 4.05, and 15.00 ± 3.03 mm, respectively. The right and left sides of average width of intermaxillary distances were measured as 13.75 ± 1.50 and 12.51 ± 1.50 mm, respectively. The average width of intermolar distance was calculated as 19.82 ± 1.61 mm (right side) and 18.89 ± 1.69 mm (left side), respectively. The maxillary dentitions were classified as square (17%), round-square (63.5%), round (14.4%), and round V-shaped arches (5.1%). The round-square ones showed no prominent principal component. Among the maxillary arches, the round arches were characterized by small values and round V-shaped ones with the largest values. Asymmetry between the right and the left bony palate was observed. The areas with equal bony palate on both sides were present in 64.4% of the cases, and in 33.1% of the cases, bony palate was dominant on the right.

CONCLUSIONS

The primary principle in reconstructive treatment should be describing geometrical forms and mathematical details of the bony palate. Three-dimensional reference values relative to the dental arch may increase the success of individual treatment of surgical procedures and reduce possible complications. With the help of certain software, this research has made possible to investigate the variability of the dental arch and calculate the variety in measurements and thereby determining the most appropriate implant position, optimizing the implant axis and defining the best surgical and prosthetic solution for the patient.

A secondary analysis to determine variations of dental arch measurements with age and gender among Ugandans

BACKGROUND

Dental arch dimensions are useful in dental practice and in forensic odontology. Local data is essential because ethnic differences exist in dental arch dimensions. In the Ugandan population no studies had been done on dental arch dimensions. The objective of the current study was to determine the variations in dental arch dimensions with age and gender in a sample of dental casts from the Ugandan population.

METHOD

This was a secondary analysis of dental casts previously prepared using mandibular and maxillary arch impressions of 220 children (85 boys and 135 girls) aged 12-17 years recruited from schools in Kampala, Uganda. Dental arch dimensions for the maxilla and mandibular casts were taken using a digital vernier calliper. The data was analysed using the means based independent samples t test to obtain the descriptive statistics with regression analysis being used to obtain the regression coefficients and constants using STATA 12.

RESULTS

The overall maxillary dimensions were significantly smaller in females than males by 1.50 mm (95% CI -2.91 to -0.09, P = 0.04), controlling for age group. The overall dimensions of the mandible were also smaller in younger participants, though this was not statistically significant.

CONCLUSION

From this study we observed significant differences in arch dimensions between males and females that are of forensic value for this population. There is need for more study of the differences in arch dimensions with age using a larger and more age diverse study population.

Changes in lower dental arch dimensions and tooth alignment in young adults without orthodontic treatment

OBJECTIVE:

The aim of this longitudinal study, comprising young adults without orthodontic treatment, was to assess spontaneous changes in lower dental arch alignment and dimensions.

METHODS:

Twenty pairs of dental casts of the lower arch, obtained at different time intervals, were compared. Dental casts obtained at T₁ (mean age = 20.25) and T₂ (mean age = 31.2) were compared by means of paired t-test (p < 0.05).

RESULTS:

There was significant reduction in arch dimensions: 0.43 mm for intercanine (p = 0.0089) and intermolar (p = 0.022) widths, and 1.28 mm for diagonal arch length (p < 0.001). There was a mild increase of approximately 1 mm in the irregularity index used to assess anterior alignment (p < 0.001). However, regression analysis showed that changes in the irregularity index revealed no statistically significant association with changes in the dental arch dimensions (p > 0.05). Furthermore, incisors irregularity at T₂ could not be predicted due to the severity of this variable at T₁ (p = 0.5051).

CONCLUSION:

Findings suggest that post-growth maturation of the lower dental arch leads to a reduction of dental arch dimensions as well as to a mild, yet significant, increase in dental crowding, even in individuals without orthodontic treatment. Furthermore, dental alignment in the third decade of life cannot be predicted based on the severity of dental crowding at the end of the second decade of life.

Gender differences in the growing, abnormal, and aging jaw

Despite wide variations in the size and shape of the human face, head, and body, there is remarkable consistency for quantifiable gender-specific facial traits. The relationships between the growing jaws and tooth eruption are complex, but they show gender-specific trajectories in children and adolescents. Disturbances in genetic, endocrine, and nutritional regulatory controls result in gender-specific and nonspecific disorders. Gender-specific differences are also apparent in the aging jaw, with the acceleration of jawbone atrophy upon loss of teeth, especially in women.