• The korean journal of orthodontics
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• v.50 no.2
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• pp.98-107
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• 2020

Objective: The aim of this study was to compare posterior tooth inclinations, occlusal force, and contact area of adults with different sagittal malocclusions. Methods: Transverse skeletal parameters and posterior tooth inclinations were evaluated using cone beam computed tomography images, and occlusal force as well as contact area were assessed using pressure-sensitive films in 124 normodivergent adults. A linear mixed model was used to cluster posterior teeth into maxillary premolar, maxillary molar, mandibular premolar, and mandibular molar groups. Differences among Class I, II, and III groups were compared using an analysis of variance test and least significant difference post-hoc test. Correlations of posterior dental inclinations to occlusal function were analyzed using Pearson's correlation analysis. Results: In male subjects, maxillary premolars and molars had the smallest inclinations in the Class II group while maxillary molars had the greatest inclinations in the Class III group. In female subjects, maxillary molars had the smallest inclinations in the Class II group, while maxillary premolars and molars had the greatest inclinations in the Class III group. Occlusal force and contact area were not significantly different among Class I, II, and III groups. Conclusions: Premolar and molar inclinations showed compensatory inclinations to overcome anteroposterior skeletal discrepancy in the Class II and III groups; however, their occlusal force and contact area were similar to those of Class I group. In subjects with normodivergent facial patterns, although posterior tooth inclinations may vary, difference in occlusal function may be clinically insignificant in adults with Class I, II, and III malocclusions.

• The Journal of the Korean dental association
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• v.50 no.1
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• pp.22-30
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• 2012

The methods for the occlusal force measurement have long been developed. The occlusal analyzing equipment utilizing the pressure-sensitive film (Prescale) is useful for the assessment and comparison among large group of patients. On the other hand, the apparatus which uses the grid-based sensor sheet (T-scan) can be a useful assistant for acquiring the well-balanced occlusion. The device that can process the electrical input from the strain gauge which is attached to the tooth surface can collect the dynamic data of actual masticatory force. This device has been developed for the measurement of actual mastication with the food bolus and it can be a useful method for the comparison before and after the restorative treatment. Occlusal force measurement can be applied for the analysis of therapeutic action, diagnosis of crack- tooth syndrome, temporomandibul ar disease, and idiopathic implant loosening.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.364-368
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• 2013

The case report describes the occlusal rehabilitation of a male patient with Angle Class III malocclusion and its effect on maximum bite force. The main complaints of patient were masticatory difficulty and poor esthetic. The patient's expectations from the treatment were a good esthetic and function with a less invasive and relatively promptly way. Therefore, increasing of the occlusal vertical dimension (OVD) and then restoring the maxillary and mandibular teeth was chosen by the patient among the treatment options. At the beginning of treatment maximum bite force of patient was measured. Then an occlusal splint was provided to evaluate the adaptation of the patient to the altered OVD. Full mouth rehabilitation with metal ceramic restorations was made. After the completion of full mouth restoration, bite force measurement was repeated and patient exhibited increased maximum bite force. Full mouth restorative treatment in a patient with Class III malocclusion could be an effective treatment approach to resolve esthetic concern and to improve masticatory function related to maximum bite force.

• Journal of Technologic Dentistry
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• v.42 no.2
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• pp.139-145
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• 2020

Purpose: This study is for the prosthesis of dog. Observed the occlusal relation between the small dog canine and carnassial teeth. The direction of the bite force was analyzed by 3D FEM(finite element method). Methods: The mandibular canine and carnassial of dog were tested. The skull of dog was contact point confirmed by dental CAD. The skull of dog was scaned using CT and a 3D model was created. The 3D model was analyzed ABAQUS. Closing movement has been 100N, 200N, 300N, 500N, 1000N, 1500N. The Direction of bite force was confirmed. Results: As occlusal force increased, the direction of bite force appeared to (-y), (-x,-y,-z), (-x,-y), (-x,-y,+z), (-x,-y,+ z), (+x,-y) in mandibular left canine. And the direction was seen at (+x, -y), (+x,-y,-z), (+x,-y), (-x,-y,+z), (-x,-y,+z), (+x,-y). When the occlusal load is 100 N, 200 N, 300 N, 500 N, the direction of the mandibular carnassial appears as (-x, -y, -z), and when the occlusal load is 1000 N, 1500 N, the direction appears as (-x,-y). Conclusion: The mandibular canine showed irregularities in the coordinates of the direction of the bite force, and the mandibular carnassial showed regularity in the coordinates of the direction of the bite force.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.2
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• pp.281-299
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• 1995

The purpose of this study was to evaluate the degree of occlusal contact under the fixed implant prosthesis of partially edentulous patients which was hased on occlusal concept of implant prosthesis. From the patients who have free-standing implant supported prosthesis of unilateral partially edentulous area, occlusal and occlusal contact point of th enatural tooth side and implant side of light closure and heavy closure were analyzed by T-scan system throuht pre-and post-adjustment and the degree of occlusal contact was estimated by Shimstock. The following results were obtained : 1. The occlusal force of natural tooth side(NF) from mid-sagittal axis was relatively constant at light and heavy closure through pre-and post-adjustment, but the occlusal force of implant side(IF) was decreased significantly at light closure(P<0.01) and heavy closure(P<0.05) of post-adjustment. 2. Natural tooth side-implant side moment(MIMoment) fo occlusal force from mid-sagittal axis was significant(p<0.05) through pre-and post-adjustment and the deviation from mid-sagittal axis was increased at light closure of post-adjustment, but was decreased at heavy closure of post-adjustment. 3. Comparing the NF and IF, IF was greater at heavy closure of pre-adjustment, and NF was greater at light closure of post-adjustment, and the NF and IF was relatively equally distributed at light closure of pre-adjustment and at heavy closure of post-adjustment. 4. The number of occlusal contact point of natural tooth side(NC) was relatively constant through pre-and post-adjustment, but the number of occlusal contact point of implant side(IC) was significantly decreased(P<0.05) at light closure of post-adjustment, and was not significant but was lesser at heavy closure of post-adjustment. 5. Difference of the NC and IC was greater at light closure of post-adjustment, but it was less at heavy closure of post-adjustment, and therefore occlusal contact point of natural tooth side and implant side was relatively equally distributed at heavy closure of postadjustment. 6. When bilaterally distribution of occlusal force and occlusal contact point was established, degree of occlusal contact of implant suporoted prosthesis with opoosing teeth at light clousre was $34.13{\pm}21.69{\mu}m$.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.3
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• pp.492-516
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• 1995

This study evaluated the responses of mandibular bones of mongrel dogs to loaded hydro xylapatite(HA) and titanium plasma spray(TPS) coated endosseous dental implants, using unloaded ones as the control group. after HA and TPS coated implants were implanted, their bone reactions with vital bones have been observed with light and scanning electron microscope(SEM) at the three periods of the 4th, 12th and 20th week. These reactions have been also compared in a histomorphometric method. The elemental distribution state of implants and the interface neighboring bone tissues have been measured with the energy dispersive analysis of X-rays(EDAX). The following results were obtained ; 1. The light microscopic analysis showed osseointegration in both the control group and the occlusal force loaded group ; Its degree was shown to be higher in the long-maintained and occlusal force groups. 2. The SEM analysis showed that both groups had osseointegration, In the case of TPS-coated implants, the coated layer was divided on the bone interface. In the case of HA-coated implants, there appeared a division between the metal and coated interface. 3. In the histomorphometric analysis, the measured ratio contaction bone of TPS-coated implants was $70{\pm}19$% in the case of no occlusal force ; it was $84{\pm}13$% in the case of occlusal force. The measured ratio contacting bone of HA-coated implants was $75{\pm}18$% in the case of no occlusal force ; it was $94{\pm}9$% in the case of occlusal force. However, there was no significant difference statistically(p>0.05). 4. Both groups showed that the ratio of calcium and phosphorous increased more in the bone tissues than on the bone to implant interface.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.1
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• pp.47-59
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• 2016

Purpose: The aim of this study was to investigate the changes in occlusal force after loss of the lower first molar depending on the inclination and extrusion of the adjacent and opposing teeth by using a strain gauge. Materials and Methods: Anatomic teeth were used to reconstruct the normal dental arch with loss of the lower right first molar. A uniformly thick layer of silicone was applied to the root to mimic the periodontal ligament. Four stages of dies with varying degrees of inclination and extrusion of the adjacent and opposing teeth were constructed and attached to master model interchangeably by using a CAD/CAM fabricated customized die system. The strain gauges were attached to teeth and a universal testing machine was used to determine the changes in occlusal force. An independent t-test and one-way ANOVA were performed (${\alpha}=.05$). Results: While simulating chewing food, the upper first, second premolar and lower second molar showed greater occlusal force than before extraction. When the change of adjacent teeth's occlusal force with their progressive movement after molar loss was evaluated, the difference among four die models was significant and was in the decreasing aspect (P < 0.05). Conclusion: When the lower first molar was lost and the adjacent teeth did not move yet, the occlusal force in adjacent teeth was higher than that when the lower first molar still existed. In addition, the occlusal force in the upper premolars and lower second molar decreased significantly with the progressive movement of adjacent teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.3
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• pp.121-140
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• 1991

Fifteen dental college students of Chosun University without the abnormal occlusion, the history and symptom of temporomandibular dysfunction(TMD), and who had all permanent teeth except third molar and the fifteen moderate group and the fifteen severe group classified according to Helkimo's dysfunction index among patients on the basis of the symptom of TMD were selected. The occlusal contact, occlusal force and occlusal interference in eccentric movement was studied and analyzed using T-Scan system. The result were as follows : 1. The TLR centering around midsagittal axis was located at $1.42{\pm}0.82mm$ in control group, $3.36{\pm}1.45mm$ in severe group, and as TMD was heavier, occlusal contact was located at the farther point from midsagittal axis. 2. The PLR from the first contact to the fifth contact centering around midsagittal axis was located at $1.73{\pm}1.78mm$ in control group, $3.36{\pm}1.41mm$ in moderate group, and $5.39{\pm}4.32mm$ in severe group, and as TMD was heavier, occlusal contact was located at the farther point from midsgittal axis. 3. The TFB, PFB, RFB and LFB of occlusal contact centering around incisal axis had no significant difference statistically among control group, moderate group, and severe group, and it was located at first molar. 4.The LF and RF was smaller in TMD group than in control group. 5. The LR moment of occlusal force centering around midsagittal axis was located at $178.51{\pm}139.81N.mm$ in control group, $466.25{\pm}296.47N.mm$ in moderate group, and $749.18{\pm}588.18N.mm$ in severe group. And as TMD was heavier, it was located at the farther point from midsagittal axis. 6. The RL and LL of occlusal force centering around incisal axis had not-significance statistically among control group, moderate group, and severe group, and it was at the first molar. 7. The number of occlusal interference of the eccentric movement was increased in the patients of TMD.

• Journal of Oral Medicine and Pain
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• v.18 no.1
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• pp.21-29
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• 1993

The purpose of this study was to evaluation of temporomandibulr joint space according to increasing the occlusal force on working and non-working side during unilateral bite. For the study, 22 normal adults, age ranged from 23 to 25, who had no symptoms on TMJ area and masticatory muscles and had normal or class I molar relationship were selected. Transcranial TMJ radiograph was taken during unilateral biting with sensor of Bite force checker (Nihon Kohden Kygyo Co.Ltd., Japan) on each 1st molar teeth of right and left side which were forced each 0Kg, 10Kg, 20Kg and 30Kg by use of Accurad-200 (Denar Corperation's product). The radiographs were traced on the screen, which was magnified by 5. The size of temporomandibular joint space at anterior, superior and posterior compartment were measured with Dumas's method (reference line of between squamotympanic fissure and the most inferior point of articular eminence). On the basis of this study, the following results were obtained. 1. Size of anterior TMJ space was tend to decrease on the working side and increase on the non-working side according to increasing the occlusal force, but not significant statistically (p>0.05). 2. Size of superior TMJ space was tend to increase on the working side and decrease on the non-working side according to increasing the occlusal force (p<0.05). 3. Size of posterior TMJ space was tend to decrease on both working ad nonworking side, but non significant statistically.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.91-99
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• 2000

This study was done to identify the changes of bite force and occlusal contact between before and after stabilization splint therapy. 16 female patients, accepted for orthodontic treatment at the Department of Orthodontics, College of Dentistry, Chosun University, were selected as the sample of this investigation. For comparisons, the samples of 16 were divided into just before stabilization splint, 1 month after stabilization splint, 2 months after stabilization splint, and 3 months after stabilization splint and used the T-scan system to identify the bite force and occlusal contact changes for each group. Statistical analysis of the data was carried out ANOVA tests, and Turkey tests using $SPSS/PC^+$. The results were as follows : 1. Bite force change from just before treatment to 1 month after stabilization splint therapy was statistical significantly decreased (P<0.05). 2. Bite force changes from 1 to 3 months after stabilization splint therapy showed no statistical significance (p>0.05). 3. The changes of anterior occlusal contacts showed no statistical significance regardless of the wearing periods of stabilization splint (P>0.05). 4. The changes of posterior occlusal contacts from just before treatment to 1 month after stabilization splint therapy was statistical significantly decreased (P<0.05). 5. The changes of posterior occlusal contacts Outing 1 to 3 months after stabilization splint therapy showed no statistical significance (P>0.05). 6. Posterior teeth rather than anterior teeth were more influenced by the changes of the number of occlusal contacts. To sum up above results, we may respect to capturing and stabilizing centric relation Position just 1 month after stabilization splint therapy.