• The Journal of Korean Academy of Prosthodontics
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• v.59 no.2
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• pp.210-219
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• 2021

Excessive teeth wear can lead to reduced chewing efficiency, occlusal plane collapse, and facial changes. Full mouth rehabilitation with a change in vertical dimension may cause pain in the temporomandibular joint, masticatory muscle and teeth, so an accurate diagnosis and treatment plan is required. In this case, a 69-year-old man had excessive teeth wear with a loss of posterior support. We evaluated the degree of adaptation to the increased vertical dimension with the removable occlusal splint and provisional restoration. We report this case because the treatment result has been functionally and aesthetically satisfactory by providing stable anterior guidance, proper posterior teeth disclusion, and even contact of all teeth in centric occlusion.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.3
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• pp.158-167
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• 2023

As digital technology has advanced in the field of dentistry, the use of computer-aided design/computer-aided manufacturing (CAD/CAM) has brought changes to the stages of dental treatment. The use of CAD/CAM technology in dental restoration offers clinical efficiency and convenience by reducing production time and appointment intervals, while also simplifying the fabrication process to reduce errors. In this case, digital replication and printing of temporary teeth were used to aid a patient with complex medical histories and physical disabilities. The final impression obtained with silicone impression material included information on the vertical dimension, centric relation, and the angle and length of the anterior teeth, which shortened the production time and appointment intervals and increased patient satisfaction. The final restoration was fabricated using milling and monolithic disc techniques, demonstrating appropriate stability, retention, and support, resulting in functional and aesthetic satisfaction.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.3
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• pp.168-175
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• 2023

Long-term use of inappropriate prosthesis often results in habitual closure or irregular mandibular movements. In that case, guide to the stable centric position is difficult. Therefore, by using a treatment denture, the muscles and TMJ should be stabilized and the jaw relation should be acquired with the treatment position. Compared to the conventional method, digital technology in fabrication complete denture has the advantage of reproducing a stable tooth arrangement in cases of difficult tooth alignment, minimizing laboratory errors and reducing denture fabrication time. Therefore, in this case, the final denture was fabricated by digitally reproducing the stable treatment position, vertical dimension, and lip support with a treatment denture, and satisfactory results were obtained.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.3
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• pp.191-200
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• 1998

This study was intended to perform the influence of condyle positional change after surgical correction of skeletal Class III malocclusion after orthognathic surgery in 37 patients(male 13, female 24) using computed tomogram that were taken in centric occlusion before, immediate after, and long term after surgery and lateral cephalogram that were taken in centric occlusion before, 7 days within the period of intermaxillary fixation, at the 24 hours later removing intermaxillary fixation and long term after surgery. 1. Mean intercondylar distance was $84.42{\pm}5.30mm$ and horizontal long axis of condylar angle was $12.79{\pm}4.92^{\circ}$ on the right, $13.53{\pm}5.56^{\circ}$ on the left side. Condylar lateral poles were located about 12mm and medial poles about 7mm away from the reference line(AA') on the axial tomogram. Mean intercondylar distance was $83.15{\pm}4.62mm$ and vertical axis angle of condylar angle was $76.28{\pm}428^{\circ}$ on the right, $78.30{\pm}3.79^{\circ}$ on the left. 2. In amount of set back, We found the condylar change(T2C-T1C) which had increasing tendency in group III (amount of setback : 10-15mm). but there was no statistical significance(p>0.05). 3. There was some correlation between condylar change(T2C-T1C) and TMJ dysfunction. It seemed that postoperative condylar change had influenced postoperative TMJ dysfunction, through there was no statistical significance (p>0.05). As we have observed the change of condylar axis in the group that complained of TMJ dysfunction in cases of large amount of mandibular setback. So we consider that the more trying to conserve condylar position will decrease occurrence rate of post operational TMJ dysfunction.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.2
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• pp.235-248
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• 1991

This study was designed to evaluate the diagnostic effect of the simulatneous multifilm individualized lateral tomography in the diagnosis of the temporomandibular disorders. The subjects consisted of 29 patients with symptoms of the temporomandibular disorders. The panoramic view, oblique lateral transcranial radiograph (OLTC) (Hirozontal angulation 0°, Vertical angulation 29°), submentovertex view, and simultaneous multifilm individualized lateral tomographs (SMFI) in centric occlusion (2.5㎜ thickness difference, 5 layers) were taken for the patients. This study compared the findings from each radiographs in the determining of mandibular condylar position with dual linear measurement of the subjective closest posterior and subjective closest anterior interarticular space and in the determining of bony changes on the studied 30 temporomandibular joints (TMJ) with symptoms of the temporomandibular disorders. The results were as follows: 1. The distribution of condylar position of OLTC and 5 layers of SMFI depended on the radiographs (p<0.05). The condylar position and the distribution of condylar position of OLTC were more similar to lateral sections of the SMFI than mesial sections, and in the distribution of the condylar position of SMFI, the more lateral sections of SMFI, the more concentric 2. positions. There were 10 cases in which all layers showed the same condylar position as that of OLTC. There were 3 cases in which no layers showed the same condylar position as that of OLTC. 3. In the SMFI of 30 Temporomandibular joints studied, there is 13 cases in which all five layers represented the same condylar position in the same TMJ and 11 cases in which 4 layers represented the same condylar position in the same TMJ and 6 cases in which 3 layers represented the same condylar position in the same TMJ. So at least 3 layers of SMFI represented same condylar position in the same TMJ. 4. The bony changes were not detected in conventional radiographs on the temporomandibular joint and the bony changes were not detected in simultaneous multifilm individualized lateral tomographs. The bony changes were detected in conventional radiographs on the temporomandibular joint and the bony changes were detected in simultaneous multifilm individualized lateral tomographs. SMFI provided a meams for a three dimensional visualization of the shape, the position and the extent of bony changes of TMJ.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.521-533
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• 2000

This study was investigated to evaluate the morphologic characteristics of openbite and deep bite in Class I malocclusion patients and to find skeletodental factors which contributed to vertical discrepancy in Class I malocclusion. The subjects were consisted of 40 control subjects (male 20, female 20) and 40 Class I openbite patients and 40 Class I deep bite patients. Lateral cephalograms in centric occlusion were taken, traced and digitized lot each subjects. The computerized statistical analysis were carried out with SPSS program. The results were as follows. 1. The pattern of vortical discrepancy in Class I malocclusion is mainly influenced by the skeletodental factors under palatal plane. 2. In openbite group, vortical discrepancy is prominent on anterior lower face and is closely related with skeletal factors such as mandibular form and inclination. 3. In deep bite group, dental factors such as ewe of Spee, vertical height of maxillary molar and skeletal factor such as articular angle were contributed to the vertical discrepancy. 4. The multiple regression analysis showed that overbite in Class I molar relationship was determined mainly by dental factors such as lower incisor to occlusal plane angle, curve of Spee, interincisal angle, and ODI.

• The korean journal of orthodontics
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• v.37 no.4
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• pp.272-282
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• 2007

The purposes of this study were to evaluate the nasolabial angle changes between closed lip position at centric occlusion and relaxed lip position at which the bite is open so that the lips do not touch and to elucidate the significance of the relaxed lip position for dentofacial diagnosis. Methods: The subjects consisted of 60 (35 Males, 25 Females) skeletal Class III malocclusion adult patients (mean age 23.3 years) with anterior crossbite. Results: In Class III malocclusion adult patients, there were significant differences in the nasolabial angle changes between closed lip position and relaxed lip position. Using the cluster analysis, the subjects were divided into three groups according to the pattern of nasolabial angle change: Group 1 (N = 27, 45%, $-8\;{\sim}\;1$), Group 2 (N = 30, 50%, $2^{\circ}\;{\sim}\;17$), and Group 3 (N = 3, 5%, over 18). Conclusion: The results showed that the pattern of the nasolabial angle change between closed lip position and relaxed lip position varies in skeletal Class III malocclusion patients. Thus, relaxed lip position should be taken into account when diagnostic records are obtained and analyzed to accurately to evaluate the facial soft tissues and predict facial esthetics after surgical-orthodontic treatment.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.299-313
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• 1990

The author analysed tomographic and cephalometric radiographs of 82 temporomandibular joints from 41 symptomatic patients and 40 temporomandibular joints from 20 asymptomatic young adults. The results were as follows; 1. The mean condylar angulation in control group and patient group was 21.72±6.48° 20.13±9.14° respectively and there was no significant difference between two groups. 2. The mean depth of cut was 6.63±0.38㎝ in control group and 6.57±0.46㎝ in patient group. 3. Mean height and width of condylar head were 6.66±1.83㎜, 12.42±0.49㎜ in control group and 6.22±1.36㎜, 11.93±l.92㎜ in patient group. 4. The mean height of articular fossa was 10.20±2.04㎜ in control group and 9.89±1.98㎜ in patient group. The mean width of articular fossa was 21.08±2.08㎜ in control group and 21.24±3.03㎜ in patient group. 5. In centric occlusion the superior joint space was largest (4.15±0.93㎜), followed by the posterior joint space (2.99±0.97㎜) and the anterior joint space (2.70±0.73㎜) in control group. The superior joint space (3.47±1.31㎜) and posterior joint space (3.47±7.07㎜) were same in patient group. There was significant difference in left superior joint spaces between two groups (p<0.05). 6. The condylar position in articular fossa was displaced anteroinferiorly (0.99±3.65㎜ anteriorly, 1.75±1.01㎜ inferiorly) in control group and posteroinferiorly (3.20±4.69㎜ posteriorly, 1.25±1.87㎜ inferiorly) in patient group with 1 inch opening. In maximum opening, it was displaced anteroinferiorly (6.09±3.55㎜ anteriorly, 1.38±2.47㎜ inferiorly) in control group and anteroinferiorly (1.70±5.96㎜ anteriorly, 1.37±1.85㎜ inferiorly) in patient group. There was significant difference in anteroposterior position of both condyles with 1 inch opening and maximum opening between two groups (p<0.01). 7. The mean inclination of upper central incisor and the posterior inclination of articular eminence in control group was 65.60±6.04° 58.88±9.18° in control group, and 67.14±8.41°, 59.70±9.08° in patient group respectively. There was no significant correlation between two groups.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.285-294
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• 1991

The human temporomandibular joint as a ginglymoarthrodial one has much in common with the other synovial joints of the body, but it does possess an unique charachteristic in that it must accomodate the various occlusal relations of dentition during an end point of closure. For that reason, the movement of the condyle in the temporomandibular joint is susceptible to influences from the nature of occlusion. Undue loading to the temporomandibular joint can be applied on the occasion of premature contacts in centric relation, balancing side interferences, change of occlusal surfaces due to excessive attrition, loss of tooth. Such occlusal disharmonies in association with the systemic and emotional factors may give rise to the temporomandibular disorder. On the other hand, the changes of occlusal patterns in the growing body can also have an effect on the growth of the temporomandibular joint through the alterations of functional stresses. The purpose of this study was to observe histopathologic response of the temporomandibular joint in unilateral chewing on one side exclusively for 10 months. Three dogs showing normal masticatory function were chosen. One dog aged about 12 months was for control, two dogs for experimental specimens were about 12 and 18 months old respectively. For chewing on the left side only, unilateral lower right premolar and molar were extracted in two experimental specimens. And then three dogs were sacrificed 10 months later. Frontal histologic sectioning of joints were done for the observation of the effects of one-side chewing. 24 specimens from three dogs were obtained and fixed in 10% formalin and routinly processed with H-E staining for histologic examination. The light microscopic findings were interpretated as follows: 1. Experimental specimen 1 aged about 22 months: In comparison with control and right non-chewing side, the proliferative and hypertrophic zone were increased at the mesial and lateral part of left chewing side condyle. There was no change of the articular tissue of temporal bone. 2. Experimental specimen 2 aged about 28 months: The articular tissues of adult joint were observed. The differences between the chewing and non-chewing side were not seen in the articular tissues of condyle and temporal bone.

• Restorative Dentistry and Endodontics
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• v.34 no.1
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• pp.8-19
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• 2009

The purpose of this study was to investigate the effects of four restorative materials under various occlusal loading conditions on the stress distribution at the CEJ of buccal. palatal surface and central groove of occlusal surface of endodontically treated maxillary second premolar, using a 3D finte element analysis. A 3D finite element model of human maxillary second premolar was endodontically treated. After endodontic treatment, access cavity was filled with Amalgam, resin, ceramic or gold of different mechanical properties. A static 500N forces were applied at the buccal (Load-1) and palatal cusp (Load-2) and a static 170N forces were applied at the mesial marginal ridge and palatal cusp simultaneously as centric occlusion (Load-3). Under 3-type Loading condition, the value of tensile stress was analyzed after 4-type restoration at the CEJ of buccal and palatal surface and central groove of occlusal surface Excessive high tensile stresses were observed along the palatal CEJ in Load-1 case and buccal CEJ in Load-2 in all of the restorations. There was no difference in magnitude of stress in relation to the type of restorations. Heavy tensile stress concentrations were observed around the loading point and along the central groove of occlusal surface in all of the restorations. There was slight difference in magnitude of stress between different types of restorations. High tensile stress concentrations around the loading points were observed and there was no difference in magnitude of stress between different types of restorations in Load-3.