• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.731-740
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• 1998

In the previous studies about prescription of preadjusted appliance, occlusal plane was used as a reference plane for crwon angulation (tip) measurement. But this reference plane is not parallel to the line connecting the facial axis points at which the centers of brackets are positioned (Andrews' plane), due to the curve of Spee. Therefore, we developed a new reference plane unaffected by the curve of Sun and more parallel to the Andrews' plane. It is an imaginary line connecting mesial and distal marginal ridges of each posterior tooth, and we named it 'marginal ridge plane'. In this study, crown angulations of posterior teeth of 29 normal occlusion samples were measured and measurements from both reference planes were compared. Crown angulation measurements measured from occlusal plane were different from crown angulation measurements from marginal ridge plane in the upper and lower 2nd molars (p<0.01), md 1st premolars (p<0.05). These results were analyzed as the crown angulation measurements from occlusal plane were affected by the curve of Spee. Crown angulations should be varied according to the amount of curve of Spee to maintain the continuity of marginal ridges. To solve this problem, determining bracket angulation as the bracket slot is parallel to the marginal ridge plane of each posterior teeth is recommended.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.2
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• pp.93-101
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• 2014

Purpose: The aim of this study is to investigate the typical shape of the curve of Spee in Korean and analyze the curve of Spee according to gender, age, and left and right. Materials and Methods: Among the patient of Wonkwang University Sanbon Dental Hospital taking cone beam computerized tomography, the images of 500 Koreans (311 males and 189 females) who qualifies the criteria of this study were selected and their curve of Spee were analysed in sagittal plane. Results: The mean radius of curve of Spee in Korean was 91.4 mm. There was statistically significant difference between male (94.6 mm) and female (86.1 mm) by gender, but not significant differences by age and between right and left side. Conclusion: Within the limitation of this study, the smaller radius (91.4 mm) of Korean than the 4-inch (101.6 mm) value advocated by Monson was meaned that it would be need to reconsider the application of the curve of Spee in all cases when occlusal plane is reconstructed in Korean.

• The korean journal of orthodontics
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• v.23 no.4 s.43
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• pp.485-492
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• 1993

Multiloop Edgewise Archwire(MEAW) is effective in relief the Curve of Spee in mandibular arch but up Sl down orthodontic elastics must be used with it. The purpose of this study was to analyse the effect of orthodontic elastics, like as up & down elastics, Class II elastics, and Class III elastics, and the effect of L loop in Multioop Edgewise Archwire. 1. Intrusive force of MEAW in anterior teeth was reduced and uprighting force in premolars was increased by up & down elastics. 2. Uprighting force was significintly increased with Class III elastics in multiple L loop arch wire. 3. The force of Class II elastics made molars tip mesially and Curve of Spee deep.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.323-335
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• 1998

Clinically, the curve of Spee is widely applied as a determined level of the occlusal curvature when the oral rehabilitation and the reconstruction of the prosthesis is needed at the malalignment dentition due to the missing, extrusion, and the inclination of the teeth. The purpose of this study was to analyze the curve of Spee of the occlusal curvature which influences to the occlusal form and the location three dimensionally, and then was to measure the radius and the degree of curvature of the curve of Spee and also was to investigate the influence to the cuspal inclination according to the change of the inclination of the curve of Spee which was analyzed by AutoCAD R.13 program at the gnathological cast and the cephalometric radiograph. The following results were obtained : 1. The radius of the curve of Spee was the mean of $11.74{\pm}3.64cm$ in the model, $12.75{\pm}4.63cm$ in the radiograph and there was no significant difference statistically between the model and the radiograph(P>0.001). 2. The radius and the degree of curvature of the curve of Spee showed negative correlation(r=-0.80), while the radius and the degree of curvature of the curve of Spee in relation to the length of the curve of Spee did not show correlation. 3. The case of the curve of Spee inclined to the posterior, that is. $Post.M{\theta}$ group showed the mean of $4.73{\pm}3.64$, positive correlation to the P2m, M1mm, M1dm, M2dm, and especially the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.70). 4. The case of the curve of Spee inclined to the anterior, that is, $Ant.M{\theta}$ group showed the mean of $3.28{\pm}3.59$, positive correlation to the P2m, M1mm, and also the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.78

• The Journal of the Korean dental association
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• v.45 no.8 s.459
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• pp.483-490
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• 2007

The aim of this study was to investigate the relationship between the mandibular antegonial notch and the mandibular morphology, and the curve of Spee in anteroposterior skeletal relationship. Pre-treatment lateral cephalograms were obtained from 80(male 34, female 46) adult orthodontic patients and the samples were classified into 3 categories by ANB angle($0^{\circ}$$\leq$ANB< $4^{\circ}$ Class I, $4^{\circ}$$\leq$ANB Class II, ANB< $0^{\circ}$ Class III). The curve of Spee was measured directly from the pre-treatment mandibular study cast of each patient included in this study. Pearson correlation coefficient test and multiple regression analysis in each group revealed the following results; 1. Antegonial notch depth was positively correlated with hoth lower anterior facial height(ANS-Me) in skeletal Class I, II and III groups and Id-Me height in skeletal Class I and II groups. 2. A statistically significant negative correlation was found between the depth of the antegonial notch and the curve of Spee in the Class III group. 3. Significant relationship was not found between the antegonial notch depth and any of the other cephalometric variables such as mandibular body length(Go-Gn) and ramus height(Co-Go). As antegonial notch depth increased, more vertical growth of the mandible was observed. Antegonial notch can be used as a predictor of vertical mandibular growth in the diagnosis and treatment planning of malocclusion.

• The Journal of Korean Academy of Prosthodontics
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• v.28 no.1
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• pp.95-122
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• 1990

This study was done to analyze the occlusal curve as one of the factors to be considered for maintenance of occlusal stability in the orthodontic and prosthodontic treatments. Sixty gnathological casts we.e obtained from 43 subjects with normal occlusion and 17 subjects with some of temporomandibular disorders. The occlusal surfaces of gnathologic casts were duplicated by using a Color kit SK-700 and tile reference points of X, Y coordinates were digitized by using the Summagraphic digitizer and 18AT computer system. The Z coordinates of cusp height were measured by 0.01mm measurable caliper. The mathematical computer program of least square method was used to analyze the occlusal curve arranged by three dimensional coordinates of X, Y, Z. The following results were obtained : 1. The occlusal curve of buccal and lingual cusp tips was fitted to the ellipse, and the occlusal curve of anterior teeth was fitted to a part of the circle in the analysis of conic sections. 2. The radius of Spee's curve showed individual differences, but was average 98.7mm in male subjects and 93.7mm in female subjects. 3. The radius fo Spee's curve according to the half of canine width showed the least coefficient of variation. 4. The radius of Spee's curve was not significantly relative to the lateral occlusal contacts on laterotrusion and the absence or presence of temporomandibular disorders. 5. The radius of Wilson's curve showed individual difference and the size of radius was followed by the order of 1st premolar, 2nd premolar, 2nd molar and 1st molar.

• Journal of Technologic Dentistry
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• v.38 no.3
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• pp.217-224
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• 2016

Purpose: This study aimed to generate 3-D occlusal curvatures and evaluate the relationship between the occlusal curvatures and mandibular occlusal morphology factors. Methods: Mandibular dental casts from 25 young adult Korean were scanned as a virtual dental models with a 3-D scanner(Scanner S600, Zirkonzahn, Italy). The curve of Spee, curve of Wilson, and Monson's sphere were generated by fitting a circle/sphere to the cusp tips using a least-squares method. The mandibular mesiodistal cusp inclination, buccolingual cusp inclination, and tooth wear parameters were measured on the prepared virtual models using RapidForm2004(INUS technology INC, Seoul, Korea). Wilcoxon signed-rank test was performed to test side difference, and Spearman's rank correlation coefficients were investigated to verify the correlation between occlusal curvatures and correlated factors (a=0.05). Results: The mean radii of curve of Spee were $83.09{\pm}33.94$ in the left side and $79.00{\pm}28.12mm$ in the right side. The mean radii of curve of Wilson were $66.82{\pm}15.87mm$ in the mesial side and $47.87{\pm}9.40mm$ in the distal side with significantly difference between mesiodistal sides(p<0.001). The mean radius of Monson's sphere was $121.85{\pm}47.11mm$. Most of the cusp inclination parameters showed negative correlation for the radius of Monson' sphere(p<0.05). Especially, the buccolingual cusp inclinations in mesial side of molar showed high correlation coefficients among the factors(p<0.05). Conclusion: The radius of Monson's sphere was greater than the classical 4-inch values, and the buccolingual cusp inclinations in mesial side of molar can be considered as one of the main factors correlating with the radius of Monson's sphere.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.283-298
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• 2008

Objective: The purpose of this study was to investigate changes in the mandibular dental arch from presurgical orthodontic treatment and orthognathic surgery, and to evaluate the relationships between the pretreatment records and changes of mandibular dental arch in skeletal Class III malocclusion individuals. Methods: Lateral cephalometric radiographs and mandibular study models of 31 adults with skeletal class III malocclusion were taken and measured. All measurements were evaluated statistically by ANOVA, Scheffe's Post Hoc, and paired t-test, and correlation coefficients were evaluated. Results: No significant difference in Mn-LMMC, Mn-LIE, Mn-MnOcc was detected between pretreatment and presurgical groups. Statistically significant but low correlations were demonstrated between the initial arch length discrepancy (ALD) and change in ICW, IPW1 (r = 0.492, 0.615) and change in arch length (r = 0.641). No association was seen between the initial depth of curve of Spee and change in mandibular incisor angle and arch width or arch length. Regression analysis showed that the amount of change for arch length and IPW1 could be explained by 64.0% and 75.8% of the pretreatment variables respectively. Conclusions: This study suggests that orthognathic surgery results can be predictable by measuring the pretreatment records.