• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.139-144
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• 2012

The purpose of this study was to evaluate the accuracy and reproducibility of measuring the size of unerupted permanent tooth via cone beam computed tomography(CBCT). Ten children were scanned with dental CBCT, and 3-dimensional reconstruction of the dentitions were generated CBCT. Mesio-distal dimension and buccolingual dimension of the teeth were made directly on the model with a high-precision digitalcaliper and on the CBCT by using three-dimensional dental imaging software. Reliability and accuracy were assessed by using intraclass correlation and paired $t$-tests. ($p$ <0.05) The results were as follows : 1. Intraclass correlations were above 0.9 for Both the CBCT and the model measurements, showinghigh reliability. 2. Although there were high correlation values(r=0.91) between CBCT and model messurement methods, comparisons between the CBCT and model messurement methods showed a statistically significant difference($p$ <0.05). 3. The CBCT measurements tended to slightly underestimate by 0.2 mm. But, the systematic difference of CBCT measurements were clinically acceptable Therefore, CBCT measurement method can be used to measure the size of unerupted teeth in a sufficiently accurate way.

• The korean journal of orthodontics
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• v.25 no.4
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• pp.447-451
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• 1995

The purpose of this study was to investigate the effects of cleft on mesiodistal dimensions of permanent teeth in unilateral cleft lip and palate patients. Mesiodistal dimensions of permanent teeth were measured to the nearest 0.01mm on plaster models of 50 subjects with unilateral complete cleft lip and palate, 10 siblings and 50 Controls. The results were as follows : 1. Tooth size discrepancy in the cleft group was significant in all regions except maxillary cuspid, mandibular cuspid and mandibular first premolar. 2. Some of the mesiodistal dimensions of the teeth on the cleft side were significantly smaller than those of their antimeres on the non-cleft side in the cleft group. 3. A comparison of mesiodistal dimensions of the teeth for the right and left sides of the control group showed no statisically significant differences excepts maxillary lateral incisor. 4. Asymmetries of mesiodistal dimensions of the teeth in the sibling group was not found except maxillary first molar.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.43-52
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• 2000

Hemifacial microsomia ( HFM ) is the second most common craniofacial abnormalies. HFM represnted a spectrum of clinical findings such as hypoplasia of the mandibular ramus and condyle, confinement of maxilla growth, external and/or middle ear defects, involvement of some cranial suture, buccal soft tissue, facial nerve, and muscles in the affected side. HFM often showed progressive facial asymmetry and occlusal plane slanting to the affected side with growth. There were several reports about asymmetry of tooth maturation, hypodontia, delayed eruption, enamel hypoplasia in HFM. Since teeth develope in close association with size and morphology of the maxillary and the mandible, it is highly likely that dental changes will be present in HFM. So the Purpose of this study was to investigate the differences of the primary and the permanent teeth dimensions in the maxillary and the mandibular dentition between the affected and the non-affected side of HFM.. The sample of this study consisted of 34 unilateral HFM Patients (18 males and 16 females, average age : 5 year 11 months old). The authors examined the mesiodistal and the faciolingual dimensions of the primary and the permanent teeth and performed statistical study by using paired t-test. The results were as follows 1. The mesiodistal dimensions of the mandibular second primary molar and the mandibular first permanent molar in the affected side of HFM were significantly smaller than those of non-affected side. But there were no significant differences in the anterior teeth and the mandibular first primary molar. It means that a gradient of severity from anterior teeth to posterior teeth was found in the mandibular dentition. 2. Although there were no significant differences in the faciolingual dimensions of the primary and the permanent teeth in the maxillary and the mandibular dentition between the affected and non-affected side of HFM, there were general trend of compensatory increase in faciolingual dimension of the mandibular primary and the permanent teeth in the affected side Therefore these results showed that HFM might affect on the abnormality of tooth dimension, especially the most posterior teeth, in the affected side of the mandible.

• The korean journal of orthodontics
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• v.25 no.5 s.52
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• pp.593-604
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• 1995

Mandibular incisor crowding is one of the most common features of malocclusion and is interesting characteristic in view of relapse and stability after orthodontic treatment. There are many potential factors in the etiology of lower anterior crowding. The tooth size variation is one of them, but biologic significance for the faciolingual width of the teeth has been overlooked. Peck and Peck reported that persons with ideal mandibular incisor alignment were shown to have incisor with smaller mesiodistal and larger faciolingual dimensions than persons with incisor crowding. On the basis of these findings they suggested MD/FL index as a clinical guideline for the assessment for lower incisor crowding. The present study was undertaken to examine the relationship between mandibular incisor crowding and mandibular incisor dimension, and determine their correlation with arch length discrepancy. 154 dental casts of people from 11 to 17 years of age were made, and were divided into normal group with irregularity index less than of 1, and crowding group with irregularity index greater than 1.The casts were measured and analyzed statistically. The results were as follows. 1. The mean mesiodistal width for mandibular incisor was larger in crowding group, and has significant difference in central inciosr measurement. There are no significant differences in the faciolingul width and MD/FL index. 2. Irregularity index has significant correlation coefficients with mesiodistal width and MD/FL index for mandibular incisor in crowding group, but no correlation with faciolingual width. It also has correlation with maxillary and mandibular arch length discrepancy, total tooth material, mandibular intercanine width, and mandibular inter first premolar width. 3. Upper and lower arch length discrepancy have significant correlation with mesiodistal width of mandibular incisor and overbite, but have no correlation with faciolingual width. Lower arch lenth discrepancy has significant correlation with MD/FL index for mandibular incisor and upper arch length discrepancy has correlation with MD/FL index for mandibular lateral incisor. 4. Significant differences were observed between normal and crowding group for the mandibular arch length discrepancy and overbite.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.115-126
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• 2000

Dental arch expansion is one of the method used to solve the dental crowding problem by non-extraction. Many formulae using tooth size have been suggested to predict ideal inter-premolar and inter-molar width. The purpose of this study was to evaluate the adequacy of some upper dental arch width prediction methods, namely Pont's method, Schmuth's method and Cha's method. The sample consisted of the casts of 119 Korean young adults who had no muscular abnormality, no skeletal discrepancy, and Angle's Class I molar relationships. Measurements were obtained directly from plaster casts; they Included mesiodistal crown diameters of the four maxillary incisors, as well as maxillary inter-first-premolar and inter-first-molar arch widths as specified by Pont. The correlation coefficients between the sum of incisors(SI) and upper dental arch width were calculated. The differences between predicted width and actual width were classified as overestimated, properestimated, and underestimated. The data obtained from each group were analyzed for statistical differences. The results were as follows : 1. Upper dental arch width indices were calculated from SI in normal occlusion (81.96 : premolar index, 62.55 : molar index). 2. Low correlations between SI and arch width were noted in normal occlusion (0.50 in the inter-premolar width, 0.39 in the inter-molar width). 3. Pont's formula and Schmuth's formula tended to overestimate the inter-premolar width. A more even distribution of estimates was noted in Cha's fomula. 4. Cases within $\pm$1 mm range of observed inter-premolar width were $45\%$ in the Cha's formula, $40\%$ in the Pont's formula, and $39\%$ in the Schmuth's formula. 5. All formulae had a tendency to underestimate the inter-molar width, but Cha's formula had better predictability than others. 6. Cases within $\pm$1 mm range of observed inter-molar width were $40\%$ in the Cha's formula, $29\%$ in the Pont's formula, and $13\%$ of Schmuth's formula. The data presented in this study does not support the clinical usefulness of ideal arch width prediction methods using the mesiodistal width of maxillary incisors.

• The korean journal of orthodontics
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• v.18 no.2
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• pp.407-420
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• 1988

The primary objective of this study was to make the prediction percentile tabulation of the sum of mesiodistal widths of the unerupted permanent canines and premolars derived from the sum of mesiodistal widths of the erupted permanent incisors in normal and crowding groups. Crowding group consisted of 85 pairs of dental casts (42 males and 43 females) with more than 4mm of crowding in anteriors. Normal group consisted of 109 pairs of dental casts (65 males and 44 females) with less than 1mm of spacing or crowding in anteriors. The mesiodistal crown diameters of permanent teeth were measured from the dental casts using the sliding calipers (Mitutoyo Co., Japan). From the study, the obtained results were as follows: There were not significant differences between male and female in both groups on the basis of the ratios between the sum of mesiodistal widths of incisors and the sum of mesiodistal widths of canines and premolars. There was not significant difference between two groups on the basis of the ratio between the sum of mesiodistal widths of mandibular incisors and the sum of mesiodistal widths of mandibular canines and premolars and was significant differences between two groups on the basis of the ratio between the sum of mesiodistal widths of mandibular incisors and the sum of mesiodistal widths of maxillary canines and premolars. There was significant difference between two groups on the basis of the ratio between the sum of mesiodistal widths of maxillary incisors and the sum of mesiodistal widths of mandibular canines and premolars. There was significant difference between two groups on the basis of the ratio between the sum of mesiodistal widths of maxillary incisors and the sum of mesiodistal widths of maxillary canines and premolars. The percentile prediction tabulations were made in an attempt to predict the sum of mesiodistal widths of the unerupted permanent canines and premolars derived from the sum of mesiodistal widths of the erupted permanent mandibular incisors in each group. The percentile prediction tabulations were made in an attempt to predict the sum of mesiodistal widths of the unerupted permanent canines and premolars derived from the sum of mesiodistal widths of the erupted permanent maxillary incisors in each group.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.115-124
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• 2002

The purpose of this study was to establish regression equations and probability charts for predicting the sum of mesiodistal crown diameters of unerupted unilateral canine and premolars from the sum of mesiodistal crown diameters of four mandibular incisors in Korean male and female. The plaster casts of 162 children(75 boys and 87 girls) among the contestees in 1994-2001 Healthy Dentition Contest in Seoul were measured. Sex differences are compared and the following results were obtained: 1. Bilateral comparison of sum of widths of permanent canine and premolars showed no significant differences for either sex(p>0.05). Sum of widths of permanent canine and premolars of male were significantly larger than that of female(p<0.01). 2. Regression equations for the prediction of sum of widths of permanent canine and premolars in each sex were as follows Male ${\Sigma}Maxillary$ 345 y= 10.45+0.53x Male ${\Sigma}Mandibular$ 345 : y= 10.07+0.51x Female ${\Sigma}Maxillary$ 345 : y=12.65+0.42x Female ${\Sigma}Mandibular$ 345 : y=11.70+0.42x Male+female ${\Sigma}Maxillary$ 345 y=11.01+0.50x Male+female ${\Sigma}Mandibular$ 345 : y=9.87+0.51x

• The korean journal of orthodontics
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• v.29 no.4 s.75
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• pp.491-501
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• 1999

Precise and accurate measuring of tooth size is essential procedure in orthodontic diagnosis. The purpose of this study was to evaluate the reproducibility and accuracy of tooth size measurements with regard to tooth and investigator. Five investigators measured the size of one side of teeth, from central incisor to first molar, on 20 sets of casts that show a moderate degree of crowding. Mesio-distal width was measured with digital vernier calipers in each tooth and this procedure was repeated three times at two weeks interval. To obtain a standard measurement for each tooth, dental casts were cut into individual tooth, and its width was measured with micrometer. The difference between the measurement from dental cast and the standard measurement was defined as the measurement error. Through various statistical analyses, following results were obtained. 1. The reproducibility did not show significant differences with regard to tooth or investigator. 2. The measurement error showed some difference with regard to tooth and investigator. 3. The magnitude of the measurement error showed increasing tendency from anterior to posterior teeth with maximum value in the first molar. 4. While the measurements obtained on study casts generally showed smaller number compared to standard measurements, the direction of the difference showed variability according to tooth or investigator. 5. The measurement errors did not show significant correlations with the degree of crowding. The results of the present study indicate that the possibility of tooth size measurement error should be taken into consideration when diagnosing an orthodontic case.

• The korean journal of orthodontics
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• v.26 no.3
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• pp.225-239
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• 1996

This study was carried out as a part of the semi-longitudinal study on growth and development of Korean children, with purpose of observing the growth change in arch form., 736 pairs, of study models were taken for 3 years. Mesio-distal diameter of each tooth, intercanine width, intermolar width, canine arch depth, molar arch depth and arch perimeters were measured. Afterwards, mean value and each standard deviation of each age group and each gender were obtained, and corresponding graphs were drawn. The following conclusions were obtained : 1. Mesio-distal diameters of maxillary central incisor, maxillary 2nd molar, mandibular canine, and mandibular 2nd molar showed statistical difierences between boys and girls. 2. Intercanine width shows a gradual increase until age of 11. 3. Intermolar width in maxilla shows continuous increase, and the tendency of increase is more apparent between age of 9 and 14. In mandible, various pattern was shown until age of 9, and after, a slight increase. 4. Canine arch depth shows the increasing tendency until age of 13 in maxilla and 11 in mandible. 5. Molar arch depth shows the pattern of increase until age of 10 in male and 9 in female, which is more apparent in maxilla. After age of 9 or 10,dereasing pattrn was significantly shown until age of 15 in maxilla and age of 12 in mandible. 6. Arch perimeters in maxilla and mandible showed gradual increase until age of 10, and the tendency of increase was more apparent in maxilla; however, between the age of 10 and 14, arch perimeters of maxilla and mandible showed gradual decrease which was more apparent in mandible.

• The korean journal of orthodontics
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• v.35 no.1 s.108
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• pp.23-34
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• 2005

Collective changes caused by orthodontic tooth movement evaluated in a specific treatment modality could give suggestive information on the specific treatment strategy. The aim of this study was to investigate retrospectively the characteristics of the orthodontic tooth movement during surgical-orthodontic treatment in order to provide an effective presurgical orthodontic treatment planning for the maxillary premolar extraction modality In the skeletal Class III malocclusion patient. Pre- and post-treatment dental casts of skeletal Class III malocclusion patients with nonextraction (N=:24) and the maxillary premolar extraction (N=31) were collected. The angulation and inclination measuring gauge(Invisitech Co. Seoul, Korea) was used to evaluate the orthodontic tooth movement. The changes in the maxillary and mandibular dental arch widths were also measured from the canines to the second molars. As a result, more palatal inclination change in the maxillary dentition was found with the premolar extraction modality than with the nonextraction modality. Linear regression analysis showed that the inter-arch width coordination was mainly due to the inclination changes of maxillary posterior teeth We conclude that the indications and proper treatment planning for surgical-orthodontic treatment in skeletal Class III malocclusion with maxillary premolar extraction could depend partly on the magnitude of the transverse inter-arch coordination especially in the maxillary dentition.