Prevalence of primate and interdental spaces for primary dentition in 3- to 6-year-old children in Taiwan

BACKGROUND/PURPOSE

Spaced primary dentition plays a critical role in the eruption of permanent teeth and the establishment of ideal occlusion. A lack of these spaces in deciduous dentition may result in disproportionate jaw and tooth sizes. Additionally, spaced primary dentition is significantly affected by ethnic factors. However, few of these studies have been conducted in Asia. The purpose of this study was to investigate the prevalence of spaced primary dentition in Taiwan.

METHODS

One hundred and forty-seven 3- to 6-year-old Taiwanese children (58 girls and 89 boys) were recruited for a cross-sectional study. Primate and interdental spaces were recorded by intraoral photos. The prevalence of spaced dentition was evaluated. The interpersonal agreement of spaced dentition between the upper and lower arches was also assessed.

RESULTS

Most of the subjects had spaced primary dentition. The prevalence of primate space was 83.7% in the upper arch and 61.2% in the lower arch, whereas the prevalence of interdental space was 44.2% in the upper arch and 53.1% in the lower arch. The prevalence rates of interdental space and upper primate space were significantly higher in boys than in girls. Interdental spaces of the lower arch increased with age.

CONCLUSION

Ethnic factors can affect the ratio of spaced dentition. Most of the 3- to 6-year-old Taiwanese children have spaced dentition. The boys have higher incidence of spaced dentition than the girls. Furthermore, primate space is more frequently found in the upper arch than in the lower arch, whereas interdental space is reversed.

[Cytocompatibility of Co-Cr ceramic alloys after recasting]

PURPOSE

To study the correlation between apical foramen area and accuracy of PropexII electronic apex locator under destroyed apical constriction.

METHODS

Forty extracted teeth with single straight root canal were ground down 1 mm in the root tip and placed in 2% liquid agar gel injected into Castro model. The length of root canal was measured by PropexII electronic apex locator. The difference (L) between the electronic length (LP) and actual length was calculated. Imaging of apical foramen was recorded under microscope and apical foramen area (S) was measured by image processing software Photoshop CS. SPSS 22.0 software package was used to analyze the linear correlation and regression.

RESULTS

With ±0.5 mm as the allowable range, all value of L was positive. The precise rate of PropexII was 52.5% when apical constriction was destroyed. There was a linear relationship between S and L (S=0.04+0.11×L，R=0.903）.

CONCLUSIONS

The accuracy decreases when apical constriction is destroyed. The accuracy is worse when the apical foramen area is larger.

Prevalence of the number of cusps and occlusal groove patterns of the mandibular molars in a Saudi Arabian population

A dental trait in humans can be a valuable diagnostic tool in anthropological studies for classifying and characterizing different ethnic groups. Many studies have attempted to relate the prevalence of dental morphologies with different factors. Several variations, such as variations in the size, number of cusps, and groove pattern, have been observed in the mandibular molars of diverse populations. The morphological features of the occlusal surfaces of the mandibular molars have been described by Gregory and Hellman. To date, no studies have been reported in the literature regarding the frequency and expression of different types of cusps and the occlusal groove patterns in a Saudi Arabian population. The present study aimed to determine the prevalence of different occlusal morphologies (number of cusps and occlusal groove patterns) of the permanent mandibular first and second molar in a Saudi population and to correlate its importance in forensics, if any. The results of this study showed that the most frequent occlusal configurations were the 5-cusp pattern seen in 85% (136 teeth) and the 4-cusp pattern seen in 11% (18 teeth) of the mandibular first molars, bilaterally. Regarding the mandibular second molars, the 4-cusp form was the most common occlusal configuration, seen in 82% (132 teeth), followed by the 5-cusps type, seen in approximately 16% (26 teeth), bilaterally. Statistically significant (P value = 0.001) differences were noted for the permanent mandibular first and second molars between male and female subjects in all cusp and groove patterns ("Y" and "+" patterns). Similarly, significant differences (P value = 0.001) were found between the unilateral and bilateral presence of different cusp and groove patterns, both in the mandibular first and second molars. The present study showed that the groove pattern in the mandibular first molars was very different when compared to other populations. The cusp and groove patterns of the mandibular second molars were similar to those of the East African and Iranian populations. The results of this study may be used in forensics. Thus, the outcomes of this study may be helpful in both anthropological and clinical dental research.

Changes in the buccolingual inclination of first molars with growth in untreated subjects: A longitudinal study

OBJECTIVES

To assess longitudinal changes in the buccolingual inclination of the maxillary and mandibular first molars in untreated male and female subjects.

MATERIALS AND METHODS

Forty-seven male and 48 female subjects whose longitudinal dental casts were available at ages 6-16 years, with normal maxillary and mandibular arch forms were included. The original casts at ages 6, 7, 8, 9, 10, 12, 14, and 16 years were digitized and standardized. Measurements were recorded as the differences in cusp heights in the vertical dimension for the mandibular and maxillary first molars using OrthoInsight software.

RESULTS

On average, for boys from age 6 to 16 years, both maxillary and mandibular first molars uprighted with age. Maxillary molars uprighted 0.403 mm on the left and 0.418 mm on the right; mandibular molars uprighted 0.441 mm on the left and 0.589 mm on the right. Similarly, for girls from age 6 to 16, both maxillary and mandibular molars uprighted with age. Maxillary molars uprighted 0.67 mm on the left and 0.574 mm on the right; mandibular molars uprighted 0.358 mm on the left and 0.329 mm on the right.

CONCLUSIONS

Maxillary molars erupted with buccal crown inclination at age 6 in both boys and girls and uprighted lingually with growth. At age 16, maxillary molars were not completely upright but rather maintained some buccal crown inclination. Mandibular molars erupted with lingual crown inclination at age 6 and uprighted buccally with age. At age 16, mandibular molars were not completely upright but rather maintained some lingual inclination.

Influence of Periodontal Biotype on Root Surface Exposure During Orthodontic Treatment: A Preliminary Study

The aim of this study was to investigate the role of periodontal biotype in the development of gingival recession in patients who have undergone orthodontic treatment. A total of 60 mandibular incisors were analyzed. The qualitative assessment of periodontal biotype was performed with the use of a new biotype probe. A strong correlation was found between thin biotype and proinclination in terms of recession depth and keratinized tissue width. Patients with thin periodontal biotype are more prone to gingival margin instability, irrespective of the type of orthodontic movements. Thin periodontal biotype and proinclination orthodontic movement were related to loss of keratinized tissue width.

Buccolingual inclination of first molars in untreated adults: A CBCT study

OBJECTIVE

To evaluate the buccolingual inclinations of maxillary and mandibular first molars in untreated adults.

MATERIALS AND METHODS

Fifty-nine subjects (14 males and 45 females; mean age, 41.2 years) with no missing teeth, no crossbite, and minimal crowding were included. For each subject, a CBCT was taken. The long axis of each first molar was determined, and the inclination of each molar was measured using the long axis and the floor.

RESULTS

One hundred seventeen out of 118 mandibular first molars measured had a lingual inclination, with a mean of 12.59° ± 5.47°. For the maxillary first molars, 107 out of 118 had a buccal inclination, with a mean of 4.85° ± 4.22°.

CONCLUSIONS

There is a curvature to the inclinations of first molars in untreated adults, where the maxillary molars have a slight buccal inclination and mandibular molars have a slight lingual inclination.

Bilateral symmetry of anterior maxillary incisors: evaluation of a community-based population

The final outcome of dental treatment needs to be not only clinically sufficient, but also esthetically pleasing. Bilateral symmetry in the maxillary incisor teeth is of significant importance in esthetic dentistry. In restorative dentistry, symmetry refers to the appearance of balance around the dental midline. The purpose of this study was to measure and compare the maxillary incisor teeth dimensions from both sides of the dental midline, in order to asses if this symmetry occurs naturally. From the student community population at Tel Aviv University, 66 students between the ages of 20-35 (35 males, 31 females) were enrolled and gave consent. The inclusion criteria for this study were: upper maxillary incisors that have never undergone restorative or rehabilitative treatment, and no history of orthodontic treatment. Standardized digital photographs were taken, and the length and width of the maxillary central and lateral incisors were measured and proportions were calculated. SPSS was used to compare the measured differences between teeth on the left versus right of the midline. Tooth proportions were not significantly different between the left and right sides. Asymmetry was found only between the lengths of the maxillary lateral incisors (p=0.009); the width for these teeth was symmetrical. A significant statistical difference was not found on most parameters when evaluating symmetry of the upper incisors. Therefore, when treating the esthetically important anterior of the mouth, care must be taken to ensure bilateral symmetry to mirror the natural symmetry found in most patients.

Evidence favoring a secular reduction in mandibular leeway space

OBJECTIVE

Researchers have documented secular trends in tooth size among recent generations. This study was a test for a change in mandibular leeway space.

MATERIALS AND METHODS

Dental casts from participants in the Denver Growth Study (23 boys, 22 girls; born in the 1930s) were compared with casts from a contemporary series of orthodontic patients (23 boys, 22 girls; born in the 1990s). All were phenotypically normal, healthy American whites.

RESULTS

Analysis of variance (accounting for sex) showed that the cumulative mandibular primary canine plus first and second primary molar size (c + m1 + m2) was slightly larger in the recent cohort (23.53 mm earlier vs 23.83 mm recent cohort; mean difference: 0.30 mm; P = .009), principally due to larger second primary molars (m2) in the recent cohort. In turn, the sum of the permanent canine and two premolars (C + P1 + P2) was significantly larger in the recent cohort (21.08 mm earlier vs 21.80 mm recent cohort; mean difference: 0.72 mm; P = .002). Larger teeth in the contemporary series produced a mean leeway space per quadrant of 2.03 mm versus 2.45 mm in the earlier cohort-a clinically and statistically significant reduction (P = .030). Some tooth types (primary second molar and permanent canine) were significantly larger in boys than in girls, but the sex difference in leeway space was not statistically significant.

CONCLUSION

Results suggest that mandibular leeway space is decreasing in 21st century American whites and may present a challenge to orthodontists in managing tooth size-arch length discrepancies.

Origins of the Electronic Apex Locator - Achieving Success with Strict Adherence to Business

Current history would have you believe that the evolution and development of the electronic apex locator for use during root canal procedures emanated from the work of Suzuki in 1942, which was developed as a product by Sunada in 1962. Yes, this is partly correct, however the concept of using electrical means to locate the ends of root canals was brought to the dental profession as early as 1918 by Dr. Levitt Ellsworth Custer, which was not addressed until Suzuki revisited Custer's concepts. This contribution was only one of the many that Custer proffered as he championed the use of electricity in dentistry.

Asymmetry in the Condylar Long Axis and First Molar Rotation

Asymmetric growth occurs frequently in the mandibulofacial region, but little attention has been given to asymmetry in the temporomandibular joint. The purpose of this study was to clarify the feature of asymmetry in the condylar long axis and its relation to upper first molar rotation. Records of 148 pre-orthodontic patients were used. The angle of the condylar long axis and that of the molar rotation were both larger on the left side than on the right side. Positive correlations were found between the corresponding bilateral measurements of condylar long axes and also between those of molar rotations, whereas no correlation was found between the condylar long axis and molar rotation. These findings were found in most subgroups classified by dental age, skeletal pattern, bite force balance, or gender. These results suggest that consistent left-right differences in the condylar long axis and first molar rotation are common.

Modulation of Clinical Expression of Plaque-induced Gingivitis: Effect of Incisor Crown Form

Evidence indicates that incisor crown form correlates with clinical periodontal features. It was hypothesized that incisor crown form may explain subject differences in gingivitis expression. The present experimental gingivitis study aimed to assess the effect of incisor crown form on plaque accumulation and gingival inflammation, and on individual susceptibility to plaque-induced gingivitis. Eighty-five periodontally healthy subjects were evaluated. A negative correlation was found between incisor crown width/crown length ratio and bleeding score (p = 0.045). From the 85 subjects, two groups of subjects with either ‘long-narrow’ or ‘short-wide’ incisor form were identified. The ‘long-narrow’ group had a significantly higher bleeding score than the ‘short-wide’ group (p = 0.014). No significant differences were found in the incisor crown width/crown length ratio between previously identified ‘high responder’ and ‘low responder’ subjects ( Trombelli et al., 2004a ). In conclusion, incisor crown form appears to affect the bleeding response of inflamed gingival tissues, while it exerts no influence on explaining differences in individuals’ susceptibility to plaque-induced gingivitis.

Reliability of clinical crown center to predict marginal ridge leveling

OBJECTIVE

To evaluate the null hypothesis that there is no difference between the vertical compensation necessary to level the clinical crown centers and that required to level the marginal ridges.

MATERIALS AND METHODS

Initial dental casts selected from 200 patients that met the selection criteria were included. The vertical position of the clinical crown center (VPCC) and marginal ridge (VPMR) of posterior teeth were measured in both arches using a digital height gauge with 0.01mm precision. The vertical discrepancy between the clinical crown centers (VDCC) and marginal ridges (VDMR) of adjacent posterior teeth were calculated and compared. The significance level was set at P < .05.

RESULTS

In general, vertical discrepancies between VDCC and VDMR were statistically significant (P < .05). Clinically significant differences were observed between the maxillary second premolar and first molar and between the mandibular molars. The VPCC was significantly and positively correlated with patient age.

CONCLUSIONS

Differences between VDCC and VDMR showed that the VPCC may not be an accurate predictor of marginal ridge leveling because the vertical compensation necessary to level the VPCCs is not similar to that required to level the marginal ridges, requiring caution in its utilization, mainly in teenagers.

Application of the Kvaal method for adult dental age estimation using Cone Beam Computed Tomography (CBCT)

Different non-invasive methods have been proposed for dental age estimation in adults, with the Kvaal et al. method as one of the more frequently tested in different populations. The purpose of this study was to apply the Kvaal et al. method for dental age estimation on modern volumetric data from 3D digital systems. To this end, 101 CBCT images from a Malaysian population were used. Fifty-five per cent were female (n = 55), and forty-five percent were male (n = 46), with a median age of 31 years for both sexes. As tomographs allow the observer to obtain a sagittal and coronal view of the teeth, the Kvaal pulp/root width measurements and ratios were calculated in the bucco-lingual and mesio-distal aspects of the tooth. From these data different linear regression models and formulae were built. The most accurate models for estimating age were obtained from a diverse combination of measurements (SEE ±10.58 years), and for the mesio-distal measurements of the central incisor at level A (SEE ±12.84 years). This accuracy, however is outside an acceptable range in for forensic application (SEE ±10.00 years), and is also more time consuming than the original approach based on dental radiographs.

Biometric study of the prefurcation area of human mandibular first molars

This study analyzed the length of the root trunk (RT) as well as the width and depth of the prefurcation area (PFA) of human mandibular first molars. Ninety-six human mandibular first molars that were extracted after being observed to be in poor condition both clinically and radiographically were used in this study. A contour-measuring instrument was used, and profiles of the buccal and lingual root surfaces of these teeth were traced on a millimeter-scaled paper. The profiles were recorded from the cementoenamel junction, millimeter by millimeter, up to the entrance of the furcation of each tooth. The width and depth of the PFA as well as the length of the RT were studied. After statistical analysis it was concluded that the mean widths of the PFA on the buccal and lingual surfaces were 3.68 ± 0.66 and 3.48 ± 0.51 mm, respectively; mean depths of the PFA on the buccal and lingual surfaces were 0.89 ± 0.42 and 0.82 ± 0.28 mm, respectively; and mean lengths of the RT on the buccal and lingual surfaces were 3.07 ± 0.82 and 3.54 ± 0.73 mm. Of the samples, the lengths of the RT and the PFA were coincident in 39.58% on the buccal surface and in 46.87% on the lingual surface. There is a concavity (PFA) in the RT region of all mandibular first molars, showing larger width and depth on the buccal surface. The RT was longer on the lingual surface in comparison with the buccal surface.

Posterior tooth angulations in patients with anterior open bite and normal occlusion

INTRODUCTION

The aim of this study was to compare the posterior tooth angulations in patients with open-bite malocclusion and normal occlusion.

METHODS

Lateral cephalometric headfilms of 45 untreated open-bite subjects were compared with the lateral headfilms of 45 subjects with normal occlusion in the permanent dentition. The groups were matched for age and sex distribution and compared with t tests.

RESULTS

The maxillary and mandibular premolars were more mesially angulated in relation to the bisected occlusal plane, and the first and second molars were significantly more distally angulated in the open-bite group in relation to the palatal and mandibular planes.

CONCLUSIONS

The maxillary and mandibular premolars were more mesially angulated in relation to the bisected occlusal plane and therefore do not compensate for the divergence of the palatal and mandibular planes as the molars do.

Gummy Smile and Short Tooth Syndrome--Part 1: Etiopathogenesis, Classification, and Diagnostic Guidelines

Treating patients with "gummy smiles" and improving smile esthetics has become an integral part of dentistry. It is necessary to conduct an accurate diagnosis of what may be multiple causes that coexist simultaneously. Though all causes may not be resolved following treatment, they should be identified; otherwise it might not be possible to conduct an adequate order of treatment, which could involve multidisciplinary collaboration between various dental specialists, and may lead to unexpected and unacceptable final results. The authors propose a complete adult classification of the causes identified for gummy smile (GS) and short tooth syndrome (STS) to ascertain the etiopathogenetic origin(s). Used in combination with the proposed diagnostic procedure, which involves an "outside-in" evaluation of the patient, the classification system will enable clinicians to provide patients an accurate prediction of final results and determine the treatment required.

Treatment of a "Gummy Smile": Understanding Etiology is Key to Success

When dealing with excessive gingival display it is important for the treating clinician to properly identify the etiology, as potential etiologic factors can vary widely. Treatment decisions in this case involving a patient with high lip dynamics and a "gummy smile" were complicated because treatment recommendations differed for each of the several etiologies involved. The treatment performed, which included orthodontics combined with crown lengthening and in which the final restorations were segmented anterior to posterior to give both the clinician and laboratory improved control, was designed to meet the patient's desired esthetic outcome while addressing the areas of risk established in the preoperative assessment.

Clinical Evaluation of Conventional Radiography, Radiovisiography, and an Electronic Apex Locator in Determining the Working Length in Primary Teeth

PURPOSE

This study's purposes were to: (1) compare the accuracy of conventional radiography (CR), radiovisiography (RVG), and the Root ZX mini apex locator (EAL) in determining the working length in primary teeth; and (2) determine the effect of wet/dry conditions on the accuracy of the EAL.

METHODS

Twenty-two children (six to 15 years old), with 41 root canals of primary teeth with or without resorption indicated for extraction, were selected. CR and RVG were used to determine the working length, followed by EAL, according to the manufacturer's instructions in both dry and wet fields (saline). Following extraction of the teeth, the actual working length was determined under stereo microscope (2X). The data was tabulated and statistically analyzed using one-way analysis of variance and student's t test.

RESULTS

The highest percentage of accurate working length measurements within the acceptable range of ±0.5 mm were for EAL (95.1 percent), followed by RVG (75.6 percent) and CR (75.6 percent). There were no statistically significant differences between the three techniques (P>0.05), and the readings obtained by the apex locator were not affected by resorption or the medium (wet/dry).

CONCLUSIONS

The Root ZX mini apex locator showed the most promising results, followed by radiovisiography and conventional radiography.

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.

Proximity of the Mandibular Canal to Teeth and Cortical Bone

INTRODUCTION

The proximity of the inferior alveolar canal to the mandibular molar roots may pose a risk of injury during various dental surgeries. The purpose of this study was to evaluate age-related and gender-related changes by using cone-beam computed tomography images between the roots of the second molars, mandibular cortex, and the inferior alveolar canal.

METHODS

One hundred fifty-five patients (68 men, 87 women), 20 years and older, who had previous cone-beam computed tomography scans were enrolled in this study. The patients were subcategorized by gender and age (group I, <21 years; group II, 21-40 years; and group III, >40 years). Distance between the mandibular canal (MC) and the second molar distal root apex as well as the 3 mandibular cortical regions (inferior cortex, buccal cortex, and lingual cortex) were measured.

RESULTS

In men, the second molar root apex to the MC distance was significantly shorter in group I than in group III (P < .01). In women, the second molar root apex to the MC distance was significantly shorter in group I than in group II and group III (P < .05). In both men and women, the buccal cortex of the mandible to the MC distance was significantly shorter on the right side compared with the left side (P < .01).

CONCLUSIONS

Our study shows that age, gender, and region have an influence on the location of the MC in the second molar area.

Prediction of anthropometric measurements from tooth length--A Dravidian study

BACKGROUND

Anthropometric measurement is essential for identification of both victims and suspects. Often, this data is not readily available in a crime scene situation. The availability of one data set should help in predicting the other. This study was hypothesised on the basis of a correlation and geometry between the tooth length and various body measurements.

AIM AND OBJECTIVE

To correlate face, palm, foot and stature measurements with tooth length. To derive a regression formula to estimate the various measurements from tooth length.

MATERIALS AND METHODS

The present study was conducted on Dravidian dental students in the age group 18 - 25 with a sample size of 372. All of the dental and physical parameters were measured using standard anthropometric equipments and techniques.

RESULTS

The data was analysed using SPSS software and the methods used for statistical analysis were linear regression analysis and Pearson correlation. The parameters (incisor height (IH), face height (FH), palm length (PL), foot length (FL) and stature (S) showed nil to mild correlation (R = 0.2 ≤ 0.4) except for palm length (PL) and foot length (FL). (R>0.6).

CONCLUSION

It is concluded that odontometric data is not a reliable source for estimating the face height (FH), palm length (PL), foot length (FL) and stature (S).

A Cone-Beam Computed Tomographic Study on Mandibular First Molars in a Chinese Subpopulation

The purpose of this study was to conduct a cone-beam computed tomographic (CBCT) investigation on the root and canal configuration of the mandibular first molars, especially the morphology of the disto-lingual (DL) root, in a Chinese subpopulation. A total of 910 CBCT images of the mandibular first molars were collected from 455 patients who underwent CBCT examinations as a preoperative assessment for implants or orthodontic treatment. The following information was analyzed and evaluated: tooth position, gender, root and root canal number per tooth, root canal type of the mesial root(s) and distal root(s), angle of the DL root canal curvature, distance between two distal canal orifices in the teeth with DL root, and angle of disto-buccal canal orifice–disto-lingual canal orifice–mesio-lingual canal orifice (DB-DL-ML). Most of the mandibular first molars (64.9%, n = 591) had two roots with three root canals, and most of the mesial root canals (87.7%, n = 798) were type VI. The prevalence of the DL root was 22.1% (n = 201). The right side had a higher prevalence of DL root than the left side (p<0.05). Additionally, the curvature of the DL root canal were greater in the bucco-lingual (BL) orientation (30.10°±14.02°) than in the mesio-distal (MD) orientation (14.03°± 8.56°) (p<0.05). Overall there was a high prevalence of DL root in the mandibular first molars, and most of the DL roots were curved in different degrees. This study provided detailed information about the root canal morphology of the mandibular first molars in a Chinese subpopulation.

Orthodontic treatment outcome: the relationship between anterior dental relations and anterior inter-arch tooth size discrepancy

OBJECTIVE

This study investigated the pre- (T1) and post-treatment (T2) relationship between anterior (canine to canine inclusive) inter-arch tooth size ratio and various dental and skeletal variables.

DESIGN

Retrospective longitudinal clinical study.

SETTING

Swedish Health Board Clinic 2000.

SUBJECTS

Random selection of T1 and T2 orthodontic records of 137 Swedish patients (56 male and 81 female). The sample included non-extraction (77), and four premolar extraction (60) cases across a range of dental and skeletal malrelationships.

MAIN OUTCOME MEASURES

Dental cast and lateral cephalogram measurements were recorded. Exploratory modelling investigated whether a significant relationship existed between the anterior inter-arch tooth size ratio and these measurements.

RESULTS

Data was normally distributed with no statistically significant differences between males and females (P = 0.88) and extraction and non-extraction (P = 0.52) treatment modalities with respect to the anterior ratio. T1 bivariate regression analysis failed to show a relationship (p < 0.05) between variables. T2 bivariate analysis showed a statistically significant relation between three variables and anterior tooth size ratio. Multiple regression analysis led to a final model where maxillary inter-canine width (P = 0.002) and upper arch crowding (0.001) were statistically significantly related to the anterior inter-arch ratio. The coefficient of determination was however uniformly low (R(2) < 0.2) for all variables.

CONCLUSION

The anterior inter-arch tooth size ratio was not associated with any common pre- or post-treatment variables in the population studied, therefore measurement of an anterior tooth size ratio pre-treatment was not clinically beneficial for determining anterior dental relations post-treatment.

Tooth-size Discrepancy and Bolton’s Ratios: a literature review

OBJECTIVES

To review the literature on Bolton's tooth-size discrepancies (TSD) with specific attention to the prevalence of TSD, and the possible influence of different classes of malocclusion, gender and racial group. Also examined were the validity of the standard deviations from Bolton's samples as an indicator of significant TSD, methods of measurement of TSD and their reproducibility. Based on the review, suggestions are made as to how future work could be improved.

RESULTS AND CONCLUSIONS

Studies have reported from 20 to 30% of people with significant tooth-size anterior discrepancies and 5-14% for overall TSD. Bolton's original sample was appropriate for indicating what ratio is most likely to be associated with an excellent occlusion, but was not suited to indicating the size or prevalence of significant TSD. Most studies use samples that are not likely to be representative of orthodontic patients in the UK or, indeed, elsewhere. Although some statistically significant differences have been reported, gender and racial group seem unlikely to have a clinically significant influence on Bolton's tooth-size ratios. Class III malocclusions may have larger average ratios. Computerized methods of measurement are significantly more rapid. Most studies performed or reported their error analysis poorly, obscuring the clinical usefulness of the results. Studies are needed to properly explore the reproducibility of measurement of TSD and to appropriately determine what magnitude of TSD is of clinical significance.

[The effect of curvatures on the accuracy of the electronic apex locator]

PURPOSE

To investigate the effect of canal curvatures on the accuracy of 3 electronic apex locators (EAL) in vitro.

METHODS

Alginate and 123 canals were used to mimic the situation in vitro. Three kinds of electronic apex locators including Raypex5(®), Propex(®) and Rider(®) were applied to determine the length of the canals divided into 3 groups including straight (<5°), middle (>10°,<20°) and severe (>20 °) according to the root canal curvatures. Experimental measurements and the distances (IF value) between experimental and ideal actual measurements under the same measurement environment were recorded. Paired sample t test was applied to analyze the results by using SPSS11.5 software package.

RESULTS

The results showed that with the allowance of ±0.5 mm, the accuracy ratios of straight canal, moderate and severe curvature canal were 84.6%, 81.6%, 87.5% for Raypex5(®) 76.9%,89.8%, 91.7% for Propex(®), and 92.3%, 89.8%, 87.5% for Rider(®), respectively. There was no significant difference in the accuracy between the EALs regarding three degrees of root canal curvatures.

CONCLUSIONS

The curvatures of the root canals have no influence on the accuracy of the EALs, though the difference exists in the accuracy rate among the EALs.

The mean visible labial length of maxillary and mandibular anterior teeth at rest

OBJECTIVE

To determine the mean visible labial length of maxillary and mandibular anterior teeth at rest.

STUDY DESIGN

Cross-sectional study.

PLACE AND DURATION OF STUDY

Department of Prosthodontics, Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Karachi, from October 2012 to March 2013.

METHODOLOGY

A total of 200 subjects were included. Measurements were carried out using digital caliper from the border of the lip to the incisal edges of incisor and to the cusp tip for the canines. The length of the upper lip was measured from subnasale to stomion. Statistical analyses were performed by Mann Whitney-U test and Kruskal Walli's test.

RESULTS

The age of the participant ranged between 20 and 65 years. At rest, females significantly displayed more of the maxillary central incisor (2.93 ± 1.57 mm; p=0.003), lateral incisor (1.87 ± 1.12 mm; p=0.005) and canine (0.59 ± 0.62 mm; p=0.031). With increasing age, the amount of maxillary anterior teeth visible at rest significantly decreased (p < 0.001), and increased for the mandibular teeth (p < 0.001). Subjects with shorter upper lips significantly displayed more maxillary anterior incisor structure than subjects with longer upper lip (p < 0.001).

CONCLUSION

Females displayed significantly more labial length of the maxillary anterior teeth. The mean visible labial length of maxillary anterior teeth significantly decreased with increasing age and increased for the mandibular teeth. As the upper lip length increased, the mean visible labial length of maxillary anterior teeth significantly decreased.

Evaluation of the association between embrasure morphology and central papilla recession by radiographic method

The objective of this study was to evaluate the association between embrasure morphology and central papilla recession. The central papilla was assessed in 372 adults using standardized periapical radiographs of the maxillary central incisors. The following vertical distances were measured: h1, papilla tip to contact point (PT-CP); h2, proximal cementoenamel junction to contact point (pCEJ-CP); h3, bone crest to contact point (BC-CP); and h4, bone crest to papilla tip (BC-PT). Vertical lines were measured along the long axis of the tooth. Horizontal distance was measured as w2 (distance between the two central incisors at the proximal CEJ level, ie, the interdental width). All participants were divided into four groups according to their w2 and h2 measurements: narrow-long (w2 ≤ 2 mm and h2 > 4 mm), narrow-short (w2 ≤ 2 mm and h2 ≤ 4 mm), wide-long (w2 > 2 mm and h2 > 4 mm), and wide-short (w2 > 2 mm and h2 ≤ 4 mm). A statistically significant positive relationship was evident between central papilla recession and age, and a statistically significant negative relationship was evident between age and papilla height in all study groups. The study found that occurrence of central papilla recession is significantly related to age with a wide interdental width and long pCEJCP distance. However, other factors also determine whether the interdental papilla is present or not, and further study of the interaction among these factors is warranted.

[Effects of premolar extractions on Bolton index overall ratios]

PURPOSE

To investigate the effect of premolar extraction on Bolton index overall ratios.

METHODS

Bolton index overall ratios were measured in 198 randomly chosen dental casts of three types of Angle's malocclusions before and after 4 combinations of hypothetical premolar extractions. The data was processed using SPSS 17.0 software package.

RESULTS

The overall ratios decreased in each class of Angle's malocclusion after all combinations of premolars extraction, and the decreases in combinations of 5/5 and 5/4 extractions were significantly greater than that of 4/4 and 4/5 combinations (P<0.05), but no significant difference was found between different types of malocclusion (P>0.05).

CONCLUSIONS

When formulating a treatment plan involving premolar extractions, orthodontists should consider that the Bolton overall ratios may decrease.

[Incisors with a mind of their own]

A 43-year-old man, known to have hypodontia, was bothered by his over-erupted central incisors. After the placement of implants and the accompanying crown- and bridgework, the central incisors appear to be increasingly over-erupted. The history shows that this phenomenon has already been seen in the past. Three mechanisms can be responsible for the over-eruption, specifically: continuous facial growth, over-eruption of both central incisors in the maxilla as a consequence of agenesis of opposing dentition and relapse of the orthodontic treatment as a result of the fact that orthodontic retention is not readily possible. After the central incisors were first cut in such a way that an acceptable incisal line has again been formed, the single-unit fixed dental prostheses on the front elements were replaced with porcelain ones.

Relationship between tooth dimensions and malocclusion

OBJECTIVE

To observe the difference in dimension of teeth among adult females with and without malocclusion.

METHODS

The cross-sectional study was conducted at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, Karachi, from April 2011 to April 2013, and used non-probability consecutive sampling. Mesiodistal and buccolingual crown dimensions were measured on study casts by using digital sliding caliper in 2 groups of females. Group 1 had 150 subjects with normal occlusion, while Group 2 had 234 with malocclusion. Independent t test was conducted to evaluate the difference between the dimensions of teeth of the two groups. Statistical analysis was done on SPSS version 16, and p value was considered significant at 0.05.

RESULTS

Overall, the difference between the groups showed a greater tooth dimension in the malocclusion group of population compared to the normal group, and the most significant difference was observed in the mesiodistal dimension of maxillary 2nd premolar, which was 0.9 +/- 0.6801mm greater in dimension in the malocclusion group compared to the normal group. The least difference was observed in the buccolingual dimension of the mandibular central incisor where the malocclusion group had only 0.08 +/- 0.5247mm larger mandibular central incisors in the buccolingual dimension compared to the normal group.

CONCLUSION

Mesiodistal and buccolingual crown dimensions were characteristically larger in the malocclusion group.

[A comparative study of Bolton index in the youth and middle-aged and elderly people]

PURPOSE

To Investigate the changes of Bolton index, maxillary and mandibular teeth size and teeth size discrepancy (TSD) in the youth and middle- aged and elderly people.

METHODS

One hundred ninety-one youth dental plaster casts from malocclusion patients and 63 middle-aged and elderly people with snoring or obstructive sleep apnea-hypopnea syndrome (OSAHS) patients were selected. 12 teeth size between the upper and lower first molar, width of maxillary lateral incisor, Bolton anterior and overall ratios and teeth size discrepancy were measured and calculated. Statistical analysis was performed using SPSS 13.0 software package.

RESULTS

There was no significant difference between the 2 groups in Bolton anterior and overall ratios (P<0.05 ).The mean size of the upper lateral tooth in the youth was larger than the middle-aged and elderly people(P<0.01).There was no significant difference in 6 upper or lower anterior teeth size between canine and 12 mandibular teeth size between first molar in 2 groups, but the mean teeth size in the middle-aged and elderly people was smaller.The prevalence of anterior and overall TSD in the youth was 31.4% and 42.4%,while it was 19.05% and 15.9% in the middle-aged and elderly group. There was significant difference(P<0.05) between 2 groups in width of upper lateral incisor, which was 7.46mm in the youth and 7.20 mm in the middle-aged and elderly group. Prevalence of laminal width of upper lateral incisor in patients with teeth size discrepancy was low.

CONCLUSIONS

Bolton index does not change by age. Although the teeth size in middle-aged and elderly group are smaller than the youth group, the total reduction is little without clinical significance. The laminal width of upper lateral incisor isn't the main cause for anterior or overall dental size discrepancy. Supported by Research Fund from Department of Public Health of Guangxi Zhuang Autonomous Region (GWZ2013405 and GWZ2007149).

Dentogingival complex: dimension based on biotypes

OBJECTIVE

Estimate the DGC dimensions and determine whether the DGC dimension varies by gingival biotype.

METHODS

A cross-sectional study was performed in the Undergraduate and Prosthodontic Graduate Program clinics of the School of Dental Medicine, University of Puerto Rico from August 2011 to April 2012. A total of 53 participants who needed restorative crowns in their teeth were recruited. Prior to crown preparation, the gingiva was classified as having a thin, mixed or thick biotype, according to transparency, using a standardized 15 UNC Hu-Friedy periodontal probe. The DGC dimension was measured by transulcus probing. Descriptive statistics were calculated in mesial, medial, and distal sites by phenotypes. Differences between and within the sites' DGC dimension mean were determined using a Friedman test. The level of significance was 0.05.

RESULTS

Mean DGC dimensions, in millimeters, for all sites measured were: 3.09 (95% CI: 2.91-3.27), 3.40 (95% CI: 3.18-3.62), 2.70 (95% CI: 2.51-2.89), and 3.17 (95% CI: 2.94-3.41) in mesial, medial, and distal sites, respectively. In thick, mixed, and thin biotypes the mesial sites showed greater DGC dimension means than the medial and distal (p<0.05) sites. Mean DGC dimension was greater for the thin compared to mixed and thick biotypes at mesial, medial and distal sites (p<0.001). Nevertheless, the thick biotype presented the smallest DGC mean dimensions compared to mixed and thin biotypes at the same sites.

CONCLUSION

The DGC dimensions in all sites were similar to those reported in the literature. DGC dimensions are different for thin, mixed and thick gingival biotypes.

[Preliminary study on measuring interdental papilla height and thickness of the maxillary anterior teeth based on cone-beam computed tomography]

OBJECTIVE

To investigate the features of the fill of interdental spaces by gingival papillae and the associated factors.

METHODS

Fifteen volunteers with healthy gingiva were involved in this study. The height and thickness on the alveolar crest level of 62 maxillary anterior papilla were measured radiographically with cone-beam computed tomography (CBCT) scans. A standardized periodontal probe with Williams markings was used for measurements of the papilla width on the alveolar crest level.

RESULTS

When the papilla was complete fill interdentally, the mean height of papillary tissue on the alveolar crest level (equal to contact point-bone crest) was (3.67 ± 0.51) mm. The mean thickness of papilla on the alveolar crest level was (8.38 ± 0.75) mm. The papilla height had a positive correlation with papilla thickness (r = 0.433, P < 0.001).

CONCLUSIONS

The cone-beam computed tomography can be used for clear visualization of the papilla profile and the measurements of papilla height and thickness. Thicker and wider tissue was associated with an increased likelihood of having a complete papilla fill.

Iatrogenic absence of maxillary canines: Bolton discrepancy treated with mandibular incisor extraction

This case report describes the orthodontic treatment of an adult patient with iatrogenic absence of the maxillary canines, moderate maxillary and severe mandibular dental crowding, a Bolton discrepancy with a large mandibular anterior excess, a maxillary right lateral incisor crossbite, and Angle Class II molar relationships. The treatment consisted of fixed appliance therapy, mandibular incisor extraction, tooth bleaching, and dental recontouring. This method of treatment maintained the patient's good facial appearance, improved the dental esthetics, and provided a good functional occlusion, eliminating the arch length and Bolton discrepancies and providing a good outcome with minimal undesirable effects.

Different manifestations of Class II Division 2 incisor retroclination: a morphologic study

INTRODUCTION

The aims of this study were to investigate whether there is a different transverse morphologic pattern of dental arches among patients with different manifestations of Class II Division 2 incisor retroclination and to evaluate to what extent the pattern of smaller-than-average teeth in Class II Division 2 malocclusion is common to all groups studied. This information might clarify whether different Class II Division 2 phenotypes represent a single etiology or multiple etiologies.

METHODS

The sample comprised 108 subjects with Class II Division 2 malocclusions, divided into 2 groups according to the type of incisor retroclination: group I included 43 Class II Division 2 subjects with retroclination exclusively of the maxillary central incisors, and group II included 65 Class II Division 2 subjects with retroclination of the 4 maxillary incisors. Maxillary and mandibular intercanine and intermolar widths as well as mesiodistal crown dimensions of the 4 maxillary and mandibular incisors were determined from the patients' initial study models. Mean values of all variables were compared between the 2 groups by sex with analysis of variance.

RESULTS

From the comparison between these 2 groups, no statistically significant differences were found for all transverse measurements (P >0.05). For all mesiodistal measurements analyzed, statistically significant differences between the groups were only found for the mean value of both maxillary lateral incisors' mesiodistal dimensions in both sexes (P <0.05).

CONCLUSIONS

It is not possible to attribute a characteristic pattern of dental arch-width and incisor mesiodistal dimensions to the different manifestations of incisor retroclination in Class II Division 2 malocclusion.

Dental arch parameters of the displacement and nondisplacement sides in subjects with unilateral palatal canine ectopia

OBJECTIVE

To compare arch perimeter and teeth size, number, and shape between the two sides of the dental arch-the canine displacement side (DS) and the nondisplacement side (NDS)-in subjects with unilateral palatally displaced canine (PDC).

MATERIALS AND METHODS

Orthopantomograms (OPTs) of 240 subjects with unilateral PDC and 240 OPT matching controls were used. Additionally, study casts of 100 study subjects and 100 controls were used. The age of subjects ranged between 14 and 25 years. Dental casts were digitized and several parameters were recorded.

RESULTS

The transverse width from midpalatal line to the buccal segment and the palatal area on the DS was larger than that in the NDS (P < .05 to .001), with no difference in tooth size between both sides. Maxillary second premolars, canines, and lateral incisors in the PDC group were smaller than those in control group. Peg-shaped lateral incisors were significantly more frequent in the study group (P < .001).

CONCLUSIONS

The transverse width of the DS was larger than that of the NDS. Both sides were generally smaller than those of the control group. Tooth size in the DS was comparable to that in the NDS but smaller than those of the control group. A missing or peg-shaped lateral incisor was the most common reported anomaly.

[Shape analysis of healthy gingival curve in maxillary anterior teeth in 120 Chinese youth]

OBJECTIVE

To establish the relationship of the gingival crest, the gingival curve characteristic point (inflection point, IP) and the contact points and to use it as reference to design the location of contact area in anterior teeth restoration to form the natural papillae.

METHODS

Two-dimensional gingival curve morphology analysis based on standardized digital images was done to measure the value of different points in the upper anterior teeth for 120 young Chinese.

RESULTS

In the maxillary anterior teeth, the average mesial papilla heights(MPH) of central incisors(CI), lateral incisors(LI), canines(CA) were (4.49 ± 0.86) mm, (3.64 ± 0.77) mm and (4.12 ± 0.92) mm; the average distal gingival papilla heights(DPH) were (4.09 ± 0.72) mm, (3.48 ± 0.83) mm and (4.13 ± 0.94) mm . The relationship of the gingival curve inflection points of maxillary anterior teeth with the gingival zenith and the contact points were determined in horizontal and vertical ways. In the CI, the mesial IP in X and Y axis were 0.61±0.10 and 0.26±0.07, in distal were 0.57±0.10 and 0.25±0.07. In the LI, the mesial IP in X and Y axis were 0.50±0.10 and 0.23±0.08, in distal were 0.56±0.11 and 0.26±0.08. In the CA, the mesial IP in X and Y axis were 0.52±0.09 and 0.23±0.07, the distal IP were 0.60±0.12 and 0.26±0.08.

CONCLUSION

The upper anterior teeth papillae shapes of the different teeth and gingival curves are determined with certain characteristics, and the gingival curve inflection points have some mathematical relationship with the gingival crest and the contact points.

Transverse dental changes after tooth-borne and bone-borne maxillary expansion

OBJECTIVE

Determine the differences in skeletal and dental maxillary expansion as evidenced by the degree of dental tipping and if this is symmetrical or not.

METHODS

Sixty-two patients who were diagnosed as requiring maxillary expansion treatment were recruited over an 18-month period. Patients were randomly allocated into three groups where a total of three to four cone-beam computerized tomographies (CBCT) were obtained throughout a one-year period depending on the group allocated. Landmarks used were from the first and second molars and premolars of the maxilla. For each of the eight teeth, three landmarks were identified: the root apex, alveolar bone and pulp chamber. Statistical analysis consisted in the use of MANOVA and after significant overall effects were detected, the univariate repeated measures results were analyzed along with separate ANOVA for each variable at each of the four time points.

RESULTS

There was strong overall significance for time, group, and time*group. The first and second molars saw both bone- and tooth-anchored treatment groups with significantly different dental inclination than the control group. For the second premolars, only the tooth-anchored group was significantly different from control. The tooth-anchored group was also significantly different than the control group in the first premolar measurements. For the analysis of asymmetry in dental inclination, no significant time, group, or time*group effects were seen overall.

CONCLUSION

The analysis provided evidence that dental tipping does occur in the molars for both RME treatments, while the premolars showed increased tipping in the tooth-anchored, but not the bone-anchored group.

Relationship of the inter-condylar width with mandibular inter-canine width

BACKGROUND

Aesthetic tooth selection and physiological tooth arrangement are the objectives of the complete denture fabrications. The objective of this study was to determine the relationship of the intercondylar width with mandibular inter-canine width.

METHODS

This cross-sectional comparative study was conducted in Department of Prosthodontics, Lahore Medical and Dental College, Lahore from January to June 2011. A total of 250 dentate subjects were selected according to the inclusion criteria. Maxillary and mandibular arch impressions were taken. The distance between the cusp tips of mandibular canines was measured by using vernier calliper. The intercondylar width was measured using arbitrary face bow. The width between the two condylar rods was measured with vernier calliper in millimetres. Every width was measured three times by the same operator to ensure the accuracy. Data recorded on the Performa for statistical analysis.

RESULT

Pearson correlation coefficients (r) for the inter condylar width and mandibular inter-canine are showing positive correlation and significant (r = 0.24, p = 0.005).

CONCLUSIONS

Inter-condylar width provides significant measurements for the selection of anterior teeth in edentulous patients.

Anatomical landmarks of maxillary bifurcated first premolars and their influence on periodontal diagnosis and treatment

OBJECTIVE

To assess the anatomical landmarks of the roots of bifurcated maxillary first premolars and study their effect on the diagnosis and management of periodontal disease.

METHODS

One hundred sixty-five maxillary first premolars were selected. The frequency of single-, two-rooted, and three-rooted premolars was assessed, but only the dual-rooted were used for the purpose of this study. For each tooth, the following measurements were obtained using a micrometer caliper: buccal and palatal root length, mesial and distal root trunk length, crown length, and width of the furcation entrance. The types of root trunk were classified according to the ratio of root trunk height to root length into types A, B and C. Root trunk types A, B and C are defined as root trunks involving the cervical third or less, up to half of the length of the root, or greater than the apical half of the root, respectively. The presence of any root grooves and concavities, as well as bifurational ridges, was assessed. The crown to root ratio was calculated.

RESULTS

Of the 165 maxillary first premolar teeth retrieved, 100 (60.6%) were two-rooted, 62 (37.57%) were single-rooted, and three (1.81%) were triple-rooted. Type A root trunks comprised only 7% of the examined teeth, while types B and C had more or less comparable results (46% and 47% respectively). Type B was more common in distal root trunks while type C was dominant in mesial root trunks. Bifurcation ridges were observed in 37% of the teeth; the mean root trunk length was greater in teeth with bifurcation ridges than in teeth without (7.41 mm vs. 5.96 mm). Root grooves and concavities were found in 96% of the mesial aspects of the root, and in 57% of the palatal aspect of the buccal root. The mean width of the furcation entrance was 0.89 +/- 0.19 mm (range 0.39-1.28). The average crown to root ratio was 0.69:1.

CONCLUSION

Awareness of root surface anatomical variations may help the practitioner when assessing the diagnosis, treatment plan and prognosis of periodontally involved two-rooted maxillary premolars.

Association analysis of clinical aspects and vitamin D receptor gene polymorphism with external apical root resorption in orthodontic patients

INTRODUCTION

Vitamin D is responsible for the regulation of certain genes at the transcription level, via interaction with the vitamin D receptor, and influences host immune responses and aspects of bone development, growth, and homeostasis. Our aim was to investigate the association of TaqI vitamin D receptor gene polymorphism with external apical root resorption during orthodontic treatment.

METHODS

Our subjects were 377 patients with Class II Division 1 malocclusion, divided into 3 groups: (1) 160 with external apical root resorption ≤1.43 mm, (2) 179 with external apical root resorption >1.43 mm), and (3) 38 untreated subjects. External apical root resorption of the maxillary incisors was evaluated on periapical radiographs taken before and after 6 months of treatment. After DNA collection and purification, vitamin D receptor TaqI polymorphism analysis was performed by polymerase chain reaction-restriction fragment length polymorphism. Univariate and multivariate analyses were performed to verify the association of clinical and genetic variables with external apical root resorption (P <0.05).

RESULTS

There was a higher proportion of external apical root resorption in orthodontically treated patients compared with the untreated subjects. In patients orthodontically treated, age higher than 14 years old, initial size of the maxillary incisor root superior to 30 mm, and premolar extraction were associated with increased external apical root resorption. Genotypes containing the C allele were weakly associated with protection against external apical root resorption (CC + CT × TT [odds ratio, 0.29; 95% confidence interval, 0.07-1.23; P = 0.091]) when treated orthodontic patients were compared to untreated individuals.

CONCLUSIONS

Clinical factors and vitamin D receptor TaqI polymorphism were associated with external apical root resorption in orthodontic patients.

Macrodontia, shovel-shaped incisors, and multituberculism: probable Ekman-Westborg-Julin trait

Multiple macrodontia is a rare finding and is defined as a condition in which a tooth is significantly larger than normal. Macrodontia may occur as an isolated finding, part of a group of dental anomalies, or as a component of a syndrome with multiple oral and systemic manifestations. The purpose of this paper was to report a case of macrodontia affecting all permanent teeth and exhibiting shovel-shaped maxillary and mandibular incisors and multituberculate molars and premolars. Some or all of this patient's characteristics have been reported in both males and females, with a ratio of 5:2. No inheritance pattern has been established, as these traits have generally occurred spontaneously. As more individuals are identified and as molecular techniques continue to advance, it is probable that a gene or genes responsible for macrodontia and the associated traits will be identified.

Evaluation of the accuracy of different molar teeth measurements in assessing sex

Teeth are considered to be a very useful tissue for sex determination and molars are among the most dimorphic teeth. Even though mesiodistal (MD) and buccolingual (BL) crown diameters are usually employed for sex assessment, alternative measurements like MD and BL cervical diameters as well as crown and cervical diagonal diameters have been developed. This study explores the utility of crown and cervical MD, BL and diagonal measurements of molars in sex assessment when used separately. A total of 254 permanent molars (excluded third molars) from 101 individuals (51 males, 50 females) from the Athens Collection were examined. Stepwise discriminant analysis was used to evaluate the accuracy of each diameter group in assessing sex. It was found that the accuracy ranges from 65.5 to 88.4 %. Cervical diagonal diameters are the most accurate followed by crown diagonal diameters, and crown and cervical MD and BL diameters. Therefore the high classification accuracy of diagonal diameters show that these measurements are more reliable for sex determination than the traditional MD and BL and can be considered a promising method for sex assessment from human teeth.

Prevalence of gingival biotype and its relationship to dental malocclusion

OBJECTIVE

To study the prevalence of different gingival biotypes in a sample of patients and the association between gingival biotype and different dental malocclusions.

METHODS

Two hundred adult patients (100 males and 100 females) who presented for treatment at the Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia were recruited from February 2011 to February 2012. Gingival thickness was assessed for the maxillary central incisors using the transparency of periodontal probe technique. Angle's classification of malocclusion and smoking habit were also recorded.

RESULTS

The mean age was 32.1 (+/-11.0) years. Thin gingival biotype was observed in 44.5% of the sample, of which 64% were females and 25% were males (p=0.001). Only 31.4% of current smokers had thin gingival biotype compared to 51.9% of subjects who never smoked (p=0.011). No significant association between dental malocclusions and the presence of thin gingival biotype was found (Class I = 42.9%, Class II = 44.1%, and Class III 53.9%, p=0.6).

CONCLUSION

A high prevalence of thin gingival biotype especially among females was observed. Smokers had thicker gingival biotype. No relationship was found between gingival biotypes and Angle's classification of malocclusion.

Comparison of three anthropometric techniques for tooth selection

The absence of a reliable method to assess the proper dimension of artificial teeth can lead to errors that reduce aesthetic outcomes of the dental treatment. Previous studies indicate facial anthropometric parameters as guides to estimate the width of the six maxillary anterior teeth. Nasal width, distance between the medialis angles of the eyes and mouth width were measured in young subjects Brazilian as well as the width of their six maxillary anterior teeth. Data were analyzed by ANOVA/Tukey's (p < or = 0.05). The distance between the medialis angles of the eyes is a reliable anthropometric method to indicate the width of artificial teeth similar to the natural extracted.