STATEMENT OF PROBLEMS: The concept of CR has also changed continuously. In order to find out the factors that affect the centric slide, studies were carried out to compare the forms of wisdom teeth eruption, lateral movement, premature contact in CR, and anterior movement. Research and statistical methods were based on the report by the 1980 Korean dental association. MATERIAL AND METHOD: In our study, 403 dentists in their twenties and dentistry students who could understand CR and CO (and who did not receive occlusal, orthodontic treatment, without extreme caries and large prosthodontic care) were compared with the 25 year old results. A segment of line parallel to the upper incisor was marked on the lower incisor. When seen laterally, a line perpendicular to the occlusal plane was drawn on the foremost area of the upper incisor. This line was extended to the lower incisor and the two points (points at the lower and upper incisors) were used as reference points for the CO. After guiding the occlusion to the CR, two lines were marked by using the same method that was used for the CO. The point in which these lines meet became the reference point of CR occlusion. RESULTS AND CONCLUSIONS: Results of the experiment completed in 1980 show that all 307 research members had anterior-posterior and upper-lower displacement. Displacement measurements were 0.7+/-0.4 mm for the anterior-posterior displacement, 0.99+/-0.50 mm for the upper-lower displacement,0.18+/-0.31 mm for the lateral displacement, and 1.32+/-0.67 mm for the total displacement. Results of the 2006 experiment show that all 409 research members had anterior-posterior and upper-lower displacement. The anterior-posterior displacement was 1.12+/-0.86 mm, the upper-lower displacement was 1.02+/-0.71 mm, the lateral displacement was 0.61+/-0.56 mm, and the total displacement was 1.80+/-0.99 mm. No specific differences were found between each group when comparing displacement according to the forms of wisdom teeth eruption. Since 1980, the percentage of unerupted teeth has increased from 35.16% (111/307 people) to 57.5% (236/409 people). Westernization of the Korean cranial form and intraoral structure has brought about these results. In our experiment, 26.7% (109/409 people) of the subjects were cuspid guided, while 7.3% (30/409 people) were mutually guided. No specific differences were found in the amount of displacement between the two groups. Only the subjects with anteriors coming in contact made up the largest percentage group (42.3%, 173/409 people) in our study. No specific differences were found between each group.
Adult ; Cuspid ; Dental Occlusion ; Dentistry ; Dentists ; Humans ; Incisor ; Molar, Third ; Prosthodontics ; Tooth, Unerupted

Impacted teeth are usually involved in permanent dentition but not in primary dentition. This paper reports a clinical case of unerupted mandibular second deciduous molar inferior to the second premolar.
Bicuspid ; Dentition, Permanent ; Humans ; Mandible ; Molar ; Tooth, Deciduous ; Tooth, Impacted ; Tooth, Unerupted

A dentigerous cyst is an epithelium-lined sac that surrounds the crown of an unerupted tooth or odontoma. And the most common sites of this cyst are the mandibular and maxillary third molar and maxillary cuspid areas. Clinically, expansion of bone with subsequent facial asymmetry, extreme displacement of teeth, severe root resorption of adjacent teeth and pain are all possible sequelae of this cyst. The standard treatment for a dentigerous cyst is enucleation and extraction of the involved tooth. But in large cysts, this can lead to functional, cosmetic and psychologic consequences to the patients. So recently, more conservative methods are used. We report 5 cases of dentigerous cysts in pediatric patient which were treated by a conservative approach, By this methods, we can preserve teeth and guide eruption of the teeth which are involved in cystic area.
Crowns ; Cuspid ; Dentigerous Cyst* ; Facial Asymmetry ; Humans ; Molar, Third ; Odontoma ; Root Resorption ; Tooth ; Tooth, Unerupted

Orthodontic treatment of a complex case that involves retained deciduous mandibular second molars with missing permanent successors is challenging. Usually, congenitally missing teeth are manifested with other dental anomalies that further complicate orthodontic treatment, such as retained deciduous teeth, impactions, transpositions and peg-shaped lateral incisors. Even though the long term prognosis of the retained deciduous tooth is not fully predictable, if the teeth are in good condition, the patient and clinician may incline towards a decision to preserve the deciduous teeth as long as possible. This case report demonstrates that deciduous teeth, in this case the mandibular second molars and maxillary canine, can be incorporated into final occlusion with clinically stable long-term results.
Humans ; Incisor ; Molar* ; Prognosis ; Tooth ; Tooth, Deciduous

The purpose of this study was to investigate the interrelationship of the experimental group and control group by analyzing case histories, intraoral radiographs, orthopantomographs, intraoral slide films and dental casts. The date for this study were complied from 654 outpatients of the Department of Orthodontics, Seoul National University Hospital. The following conclusions were obtained. 1. When one or more third molar teeth were congenitally missing, the incidence of the other congenitally missing teeth was high. 2. The frequency of congenitally missing teeth was comparatively higher in male, maxilla, class II and class III. 3. The congenitally missing area of the third molar by Angle's classification was not significant. 4. The order of frequency of congenitally missing teeth was the third molar, the second premolar, the lateral incisor, the first premolar, the first premolar, the central incisor, the canine, the first molar, the second molar.
Bicuspid ; Humans ; Incidence ; Incisor ; Male ; Malocclusion ; Maxilla ; Molar ; Molar, Third* ; Orthodontics ; Outpatients ; Seoul ; Tooth*

This study aimed at investigating the skeletal, dentoalveolar, and soft tissue changes of Class III malocclusion cases treated by second molar extraction. The lateral cephalograms of 15 subjects with moderate Class III malocclusion by average ANB -1.4degrees and IMPA 85degrees were traced and the computerized superimposition of average craniofacial change was made. The data was gathered and statistically analyzed. The results were as follows: 1. Lower anterior facial height/anterior facial height increased by 0.6%(P<0.01), mandibular plane increased by 1.5degrees (P<0.05). 2. There was a slightly downward & backward rotation of the mandible. 3. Lower first molar tipped distally by 4.06mm(P<0.001), lower anterior teeth lingually tipped by 3.2degrees (P<0.05). 4. Retracted lower lip improved facial profile. This study may suggest that second molar extraction could be effective for a moderate Class III malocclusion to make distalization of the lower first molar easier and avoid severe lingual tipping of the lower incisor, if the lower third molar has a normal shape, good direction of eruption and adequate time for lower second molar extraction.
Incisor ; Lip ; Malocclusion ; Mandible ; Molar* ; Molar, Third ; Tooth

Surgical removal of impacted mandibular third molars frequently require tooth sectioning or bone removal. In this study, 361 mesioangular or horizontal impacted mandibular third molars are removed surgically by tooth section, the methods of tooth section are classified as 4 stages and 12 grades in the number of times and technics of crown or roots section and difficulties. Grades and their cases are followings: 1. occlusal crown first section(100, 28%) 2. distal crown first section(69, 19%) 3. occlusal crown second section(29, 8%) 4. distal crown second section(52, 14%) 5. occlusal crown first section and root section(10, 3%) 6. distal crown first section and root section(27, 7%) 7. occlusal crown third section(3, 1%) 8. distal crown third section(22, 6%) 9. occlusal crown second section and root section(13, 3%) 10. distal crown second section and root section(17, 5%) 11. occlusal crown third section and root section(2, 1%) 12. distal crown third section and root section(17, 5%)
Crowns ; Molar, Third* ; Tooth

Most of orthodontic cases are treated with extraction of certain teeth, which influence the pre-eruptive movement of the lower third molar. The purpose of this study was to evaluate the positional change of lower third molar following orthodontic treatment. Pre- and post-treatment pantomograms of 163 orthodontic patients (77 nonextraction group, 78 first premolar- extraction group. 8 second molar- extraction group) were analyzed in terms of the mesiodistal and buccolingual angles of lower third molar. The results were as follows. 1. The change of the mesiodistal angle of lower third molar by orthodontic treatment was significant in second molar-extraction group. 2. The mesiodistal angle of lower third molar in pre-treatment was significantly correlated to the mesiodistal angle in post-treatment and/or the change of the mesiodistal angle by treatment. 3. The change of the buccolingual angle of lower third molar by orthodontic treatment was significant in non-extraction group or first premolar-extrction group. 4. The change of the buccolingual angle of lower third molar by treatment was significantly correlated to the mesiodistal angle in post-treatment, the change of the mesiodistal angle by treatment, the buccolingual angle in pre-treatment or the buccolingual angle in post-treatment.
Humans ; Molar, Third* ; Tooth

It is the aim of this study to determine the impacts of radicular development of lower third molars on its eruption/impaction and to grope the prediction for eruption and/or impaction in advance. Three hundred and thirty cases of orthopantomogram were employed and classified as mesial root-dominant group, distal root-dominant group and identical group according to the radicular development of lower third molars. This presentation has carried out the incipient mesial inclination, radicular development, impaction/eruption rate and changes of mesial inclination of the very teeth. Consequently the following summary and conclusions were drawn; Radicular development dominated mesial root than the distal and dominant mesial root invited higher potentialities for normal eruption. The mesial or horizontal impactions were detected on the distal root-dominant group. This analysis has been suggested the potential eruption/impaction of lower third molars were dependent upon the radicular development and the incipient mesial inclination.
Molar, Third* ; Tooth

The combination of submerged primary molars and permanent teeth deletion is rare. This article reported a case of several submerged primary molars, permanent teeth deletion and a cone-shaped maxillary lateral incisor and discussed based on relevant literatures.
Dentition, Permanent ; Humans ; Incisor ; Molar ; Tooth, Deciduous