• 대한치과의사협회지
• /
• 제25권9호통권220호
• /
• pp.861-872
• /
• 1987

The Purpose of this study was to know the differences between the occlusal plane angles formed by F-H plane on cephalograms and the occlusal plane angles by the upper margin of the articulator, and to ind the contributing factors to the difference of occlusal angles. for this study, 39 young adults (20 men, 19 women) were selected who had normal occlusion, no severe attrition, no missing tooth, not been under orthodontic treatment and occlusal equilibration and no temporomandibular disorders. The maxillary casts were mounted with Hanau 159-1 ear piece type face-bow and measured the occlusal plane angle with prototype occlusal plane projector. The following results were obtained; 1. The mean value of the ear rod F-H plane occlusal angle was 14.75˚, articulator occlusal angle was 9.26˚ and strong positive correlation between these angles, 2. It was almost same angle between the ear rod F-H plane angle (14.75˚) and the beyron point to infraorbital rim-6mm. occlusal angle (14.46˚) 3. The mean distance from the ear rod porion to the Byron point was 5.67mm. 4. It was no significant correlation between the distances Po-Beyron point, Or-infraorbital rim and articulator occlusal angle.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제19권1호
• /
• pp.25-34
• /
• 1997

This study was made with lateral cephalometric radiography of 28 skeletal class III malocclusion patients that were performed to setback surgery of mandible. The 28 patients were selected by four standards as follows. 1) Set-back amount of mandible is below 10 mm 2) No extrusion and intrusion of posterior tooth or alteration of interincisial angle at period of postoperative orthodontic treatment. 3) Change of mesial segment location of mandible on lateral cephalometrics 4) No genioplasty And 28 patients were divided to three group(1,2,3 group) by degree of preoperative occlusal plane angle to Burstone's horizontal plane. The preoperative occlusal plane angle, which of 1 group was smaller than $7^{\circ}$ and 2 group was between $7^{\circ}$ to $15^{\circ}$ and 3 group was larger than $15^{\circ}$. The results were as follows : 1. As the preoperative occlusal plane angle was larger, the degree of mandibular prognathism was not severe. 2. On comparsion of preoperative and immediate postoperative cephalometric analysis, specific relationship of occlusal plane angle and set-back amount of mandible was not present. 3. As the preoperative occlusal plane angle was smaller, the alteration of postoperative occlusal plane angle was increased tendency. As the preoperative occlusal plane angle was larger, the alteration of postoperative occlusal plane angle was decreased tendency. 4. The relapsed degree of B point distance to Vertical plane was not relationship to the degree of preoperative occlusal plane angle.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제29권2호
• /
• pp.141-147
• /
• 2007

The purpose of this study was to evaluate the effects of maxillary occlusal plane angle to postoperative skeletal stability by comparative analysis after two-jaw surgery of patients with skeletal CIII malocclusion. This study was made with lateral cephalometric radiography of 52 patients with skeletal class III malocclusion that were performed to Le Fort I osteotomy and BSSRO. And 52 patients were divided to Group A(n=30) and B(n=22). Maxillary posterior impaction was not conducted in Group A, which the pre-operative maxillary occlusal plane angle was in a normal range, and for Group B, which the pre-operative maxillary occlusal plane was low, the maxillary posterior impaction was conducted. The results were obtained as follows : 1. The relapse rate of Group A, which the pre-operative maxillary occlusal plane angle was in a normal range, was relatively stable compared to Group B, which the pre-operative maxillary occlusal plane was low. 2. The relapse rate of each measurement of Group B, which had the maxillary occlusal plane altered during the operation, was somewhat high, and of those, the post-operative relapse rate of overjet, overbite, mandibular plane angle appeared to be significantly high in the statistics. The analyzed results above, was thought to be indicating that the pre-operative maxillary occlusal plane angle was closely related to the post-operative skeletal stability, and that obtaining post-operative skeletal stability only through operative normalization of occlusal plane angle may meet limitations.

• The Journal of Advanced Prosthodontics
• /
• 제5권1호
• /
• pp.58-66
• /
• 2013

PURPOSE. The purpose of this study was to decide the most appropriate point on tragus to be used as a reference point at time of marking ala tragus line while establishing occlusal plane. MATERIALS AND METHODS. The data was collected in two groups of subjects: 1) Dentulous 2) Edentulous group having sample size of 30 for each group with equal gender distribution (15 males, 15 females each). Downs analysis was used for base value. Lateral cephalographs were taken for all selected subjects. Three points were marked on tragus as Superior (S), Middle (M), and Inferior (I) and were joined with ala (A) of the nose to form ala-tragus lines. The angle formed by each line (SA plane, MA plane, IA plane) with Frankfort Horizontal (FH) plane was measured by using custom made device and modified protractor in all dentulous and edentulous subjects. Also, in dentulous subjects angle between Frankfort Horizontal plane and natural occlusal plane was measured. The measurements obtained were subjected to the following statistical tests; descriptive analysis, Student's unpaired t-test and Pearson's correlation coefficient. RESULTS. The results demonstrated, the mean angle COO (cant of occlusal plane) as $9.76^{\circ}$, inferior point on tragus had given the mean angular value of IFH [Angle between IA plane (plane formed by joining inferior point-I on tragus and ala of nose- A) and FH plane) as $10.40^{\circ}$ and $10.56^{\circ}$ in dentulous and edentulous subjects respectively which was the closest value to the angle COO and was comparable with the values of angle COO value in Downs analysis. Angulations of ala-tragus line marked from inferior point with occlusal plane in dentulous subject had given the smallest value $2.46^{\circ}$ which showed that this ala-tragus line was nearly parallel to occlusal plane. CONCLUSION. The inferior point marked on tragus is the most appropriate point for marking ala-tragus line.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제29권4호
• /
• pp.239-244
• /
• 2003

The common errors in preoperative treatment plan for the orthognathic surgery can be occurred during cast impression, cast mounting procedure with face-bow transfer, surgical stent fabrication, and so on. One of the most common errors exists during mounting process of the model on the articulator. Accurate mounting of dental casts to articulator should be achieved by transferring the 3-dimensional spatial relationship of the maxillary arch to an articulator. A face-bow is used for transfer this relationship to articulator, usually by relating the face-bow to a plane of reference of maxillary cast. The purpose of this study is evaluation of the accuracy of face-bow transferring of maxillary model to the articulator. The maxillary casts of thirty patients for orthognathic surgery were mounted on articulator with an face-bow instrument. The relationship of occlusal plane angle to Frankfort horizontal plane relations were compared the cephalogram with the cast-mounted articulator. As a result of this study, the significant difference between the maxillary occlusal planes angle in the cephalogram and articulator were found. The results were followed, 1. The mean occlusal plane angle in cast-mounted articulator was $13.5^{\circ}\;(SD{\pm}5.4)$. 2. The mean occlusal plane angle in cephalogram was $10.4^{\circ}\;(SD{\pm}4.3)$. 3. The mean difference of occlusal plane angle between cast-mounted articulator and cephalogram was $3.3^{\circ}\;(SD{\pm}4.6)$. According to the result, we should suggest that the occlusal plane angle to Frankfort plane in cast-mounted articulator is more steeper than that of cephalogram. And then, maxillofacial surgeon should try to get a more predictable result by suggesting the proper correction method and mounting the cast accurately.

• 대한치과교정학회지
• /
• 제28권2호
• /
• pp.175-187
• /
• 1998

본 연구는 치료후 빈번한 재발로 인해 치료에 어려움을 겪는 III급 부정교합의 치료후 예후를 예측하는 데 도움을 주고자, 교정치료후 관찰기간동안 측모와 교합이 양호한 상태로 유지된 안정군(Stable group, n=12)과 그렇지 않고 재발의 경향을 보인 재발군(Relapse group, n=13)으로 나누고, 초진시 계측항목을 이용한 t-test, 상관분석 그리고 판별분석을 시행한 결과 다음과 같은 결론을 얻었다. 1. 상하악골의 전후방적인 위치와 관계를 나타내는 항목인 SNA, SNB, ANB, Angle of convexity 그리고 APDI에서 두 군간 통계학적으로 유의성 있는 차이를 보여주지 않아(p>0.05) 두 군간 전후방적 인 골격 형태에 있어서는 차이가 나지 않음을 알 수 있었다. 2. 교합평면의 경사도와 관련된 항목인 Wits, AB to Occlusal plane angle 그리고 Occlusal plane to Mandibular Plane angle에서 두 군간 통계학적으로 유의성 있는 차이를 보여(p<0.05)재발군의 교합평면이 안정군에 비해 전하방으로 많이 경사져 있음을 알 수 있었다. 3. 상하치열관계를 나타내는 항목인 Overjet에서 안정군이 재발군에 비해 절대치로 더 커(p<0.01) 전후방 골격부조화에 의한 것이 아닐 경우 치열의 전후방부조화가 클수록 치료후 예후가 좋음을 알 수 있었다. 4. 상관분석결과 Overjet과 Occlusal plane to Mandibular plane angle만이 통계학적으로 유의성 있는 상관관계를 보여 주었다(p<0.001, p<0.01). 5. 판별에 기여도가 높은 3항목 즉 Overjet, AB to Occlusal paine angle 그리고 Articular angle을 이용한 판별식을 도출하였으며, 이를 이용할 때 본 연구에 사용한 표본의 88%를 올바르게 판별할 수 있었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제36권5호
• /
• pp.375-379
• /
• 2010

Introduction: In the management of dentofacial deformities, variable movement of the maxilla can be made possible by a Le Fort I osteotomy. Posterior impaction of the maxilla necessary for rotation of the maxillomandibular complex enhances the functions and esthetic results. In cases of posterior impaction of the maxilla, an increase in the figure of the occlusal plane angle and incisor inclination can occur. This study reports the relationship between the amount of posterior impaction and the change in the occlusal plane angle and incisor inclination in a Le Fort I osteotomy by preoperative and postoperative lateral cephalograms. Materials and Methods: Twenty patients who had undergone orthognathic surgery in Dong-A University Medical Center participated in this study. Lateral cephalometrics, within 3 weeks prior to surgery and 3 days after surgery, were used for analysis. Pre and postoperative measurements of the occlusal plane angle and incisal inclination based on the Frankfort horizontal (FH) plane were performed. X and Y were defined as the amount of vertical change in the upper incisor tip and the amount of vertical change in the upper first molar mesial cup tip through the operation. The amount of final posterior maxillary impaction was determined by subtracting Y from X, which is the difference in vertical height. According to the amount of posterior maxillary impaction, the change in the occlusal plane angle and incisal inclination was measured. Results: The average posterior maxillary impaction was 2.91 mm and the average change in the occlusal plane angle and incisal inclination was $6.54^{\circ}$after surgery. As a result, each mm of posterior maxillary impaction changed the occlusal plane angle and incisal inclination by $2.25^{\circ}$. Statistically, there was high significance. Two cases were observed: one with the same amount of posterior maxillary impaction performed on both the right and left showing $2.20^{\circ}$, and the other with a different amount of posterior maxillary impaction performed showing $2.35^{\circ}$. In this case, there was no significance difference between the two cases. Conclusion: Each mm of posterior maxillary impaction changes the occlusal plane angle and incisal inclination by an average of $2.25^{\circ}$. In posterior maxillary impaction, there was no significant difference in the amount of change in the occlusal plane angle and incisal inclination regardless of whether there was an equal amount of posterior maxillary impaction on both sides. This study is expected to help in the presurgical orthodontic preparation and presurgical treatment planning.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제26권3호
• /
• pp.229-237
• /
• 2000

According to the functional matrix theory, Delaire proposes that individual occlusal plane was determined by variable effects of teeth, maxilla, mandible, cranium, cranial base and soft tissue matrix including the orofacial musculature. and that there is the ideal occlusal plane determined by the most proper spatial position of maxilla and mandible, functionally and esthetically. This study was designed to find out the relation between Delaire's ideal occlusal plane and muscle activity of masticatory muscles in individuals who have normal maxillo-mandibular relationships. Lateral cephalometric radiographs were taken and his/her individual occlusal plane and ideal occlusal plane were analyzed with Delaire's architectural and structural craniofacial analytic method. For evaluation of muscle activities of masticatory muscles, electromyography of anterior temporal muscle, superficial masseter muscle, and anterior belly of digastric muscle was recorded in fifty Korean normal Angle class I occlusion individuals. According to the average value of ideal occlusal plane, fifty normal Angle class I occlusion individuals were classified into three groups: Ideal occlusal plane group(I group), hyperrotation group(I+ group) and hyporotation group(I- group). The result of this study was as follows: 1. The results of Delaire's architectural and structural craniofacial analysis of lateral cephalography of the fifty Korean normal Angle class I occlusion individuals are that twelve persons(24%) have consistent or parallel with ideal occlusal plane and the average of angular difference was $1.22^{\circ}{\pm}3.69^{\circ}$. 2. There is no significant difference in muscle activities of masticatory muscles during resting(p<0.05), but significant increases of muscle activity of ipsilateral anterior temporal and masseter muscle, contralateral anterior belly of digastric muscle during unilateral chewing and of anterior temporal and masseter muscle during bilateral clenching(p<0.05). 3. To find out the effect of the angular difference between Delaire's ideal occlusal plane and real occlusal plane to muscle activity, muscle activities of masticatory muscles were compared with three groups in each other; I group, I+ group and I- group. The results were no significant differences during resting, unilateral chewing and bilateral clenching.(p>0.05) 4. Although there is no significant differences of masticatory muscle activities among the three groups, the fact that increasing tendency of masseter muscle activity of ideal occlusal plane group(I+) than those of any other groups(I+ and I-) during bilateral clenching was noted. There is only the implication that occlusal plane makes some effects on masticatory muscle activities, espacially that of masseter muscle during bilateral clenching. In conclusion, the hypothesis that occlusal plane is one of the factors which affect the muscle activities of masticatory muscles and that anyone whose occlusal plane consistent with Delaire's ideal occlusal plane has an extraordinary functional advantage in masticatory muscle function cannot be proven with electromyography methods.

• 대한치과교정학회지
• /
• 제20권2호
• /
• pp.333-354
• /
• 1990

This study was designed to analyse vertical dysplasia such as open bite or deep bite in persons with skeletal Class III malocclusion. The subjects consisted of 60 control patients, 40 Class III open bite patients and 40 Class III deep bite patients. The mean age was 19.8 years in the control group, 17.8 years in the Class III open bite group and 16.5 years in the Class III deep bite group. The results were as follows: 1. In Class III malocclusion patients, the characteristics of the vertical dysplasia are under the palatal plane. 2. In Class III malocclusion patients, the items showing the characteristics of the vertical dysplasia are mandibular plane angle, lower gonial angle, lower facial height, dental height & inclination of the upper first molar, interincisal angle, maxillary & mandibular occlusal plane angle. 3. In Class III malocclusion patients, LPFH/LAFH ratio shows the highest significance among the facial height ratios. 4. In Class III malocclusion patients, open bite group has a upward cant of maxillary occlusal plane & downward cant of mandibular occlusal plane. And deep bite group has a downward cant of maxillary occlusal plane & upward cant of mandibular occlusal plane. 5. In Class III malocclusion patients, the molar teeth of the open bite group are measially inclined and those of the deep bite group are upright.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제40권3호
• /
• pp.123-129
• /
• 2014

Objectives: The aim of this study was to verify the concordance of the measurement values when the same cephalometric analysis method was used for two-dimensional (2D) cephalometric radiography and three-dimensional computed tomography (3D CT), and to identify which 3D Frankfort horizontal (FH) plane was the most concordant with FH plane used for cephalometric radiography. Materials and Methods: Reference horizontal plane was FH plane. Palatal angle and occlusal plane angle was evaluated with FH plane. Gonial angle (GA), palatal angle, upper occlusal plane angle (UOPA), mandibular plane angle (MPA), U1 to occlusal plane angle, U1 to FH plane angle, SNA and SNB were obtained on 2D cephalmetries and reconstructed 3D CT. The values measured eight angles in 2D lateral cephalometry and reconstructed 3D CT were evaluated by intraclass correlation coefficiency (ICC). It also was evaluated to identify 3D FH plane with high degree of concordance to 2D one by studying which one in four FH planes shows the highest degree of concordance with 2D FH plane. Results: ICCs of MPA (0.752), UOPA (0.745), SNA (0.798) and SNB (0.869) were high. On the other hand, ICCs of gonial angle (0.583), palatal angle (0.287), U1 to occlusal plane (0.404), U1 to FH plane (0.617) were low respectively. Additionally GA and MPA acquired from 2D were bigger than those on 3D in all 20 patients included in this study. Concordance between one UOPA from 2D and four UOPAs from 3D CT were evaluated by ICC values. Results showed no significant difference among four FH planes defined on 3D CT. Conclusion: FH plane that can be set on 3D CT does not have difference in concordance from FH plane on lateral cephalometry. However, it is desirable to define FH plane on 3D CT with two orbitales and one porion considering the reproduction of orbitale itself.