Impacted mandibular third molars are located between the second mandibular molar and mandibular ramus. However, ectopic mandibular third molars with heterotopic positions are reported in the subcondylar or pterygomandibular space. The usual cause of malposition is a cyst or tumor, and malposition without a pathology is rare. This case report described an impacted mandibular third molar in the pterygomandibular space without any associated pathology.
Molar ; Molar, Third*

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

A study mentioned impaction related wisdom teeth are frequently seen age groups of 22- 32 years of age, taking 72% of statistic data, then corresponding with development time and growing processus of wisdom teeth. The types of mandibular wisdom teeth inclined to cause eruption complications take 83% of these cases are grouped in class II, according to Archer’s classification. The position A, and B are locating the teeth at the end of their eruption time from alveolar gingival level and are prone to cause local complications the whole situations take 94% of cases. The vertical axia orientation of these cause wisdom teeth will largely influence on the course of the following complications.
Molar, Third ; Mandibular Diseases

A prospective study was conducted on 120 patients (65 males and 55 females) with displaced wisdom tooth at the Dentistry and Stomatology Department of Hospital 103 between 9/2003 and 10/2004. Results: There was no difference between male and female. The surgery for extracting displaced wisdom tooth caused complications depending on ages 25-34 (51.16%), 15-24 (37.5%), 35-45 (8,33%). Patients need examination and treatment for pain (55.85%), swelling (11.66%), choking on food (29.16%) and the other causes (33.3%). Two kinds of displaced wisdom tooth that have high rates were: Mesio–angular wisdom tooth: (54.16%), vertical wisdom tooth, jaw-bone clamp (22.5%)
Molar, Third ; Epidemiology

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

This study was designed to recognize the factors which can affect the normal eruption of the lower third molar and the eruption rate of the lower third molar in the cases of non-extraction and the extraction of first premolar. The sample consisted of 214 cases of extraction of first premolar and 119 cases of non-extraction, and all of these cases were divided into erupted and impacted lower third molar groups and were analized according to the pantomogram. The results of the study were as follows : 1. The eruption rate of the lower third molar was 54.67 % in the group of extraction of the first premolar and 35.29 % in the non-extraction group. 2. The early inclination of the erupting lower third molar has significant effect in the eruption of it. 3. In the orthodontic treatment, the extraction of first premolar is one of the factors influencing the normal eruption of lower third molar. 4. The available space for the normal enruption of lower third molar was greater in first premolar extraction case than in non-extraction case.
Bicuspid* ; Molar, Third*

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

OBJECTIVES: Pericoronitis was the most common indication for mandibular third molar surgery and there are no universally acceptable predictive criteria for pericoronitis occurrence. This study was designed to analyze the correlation of the pericoronitis and the eruption state of the mandibular third molar using panoramic radiographs statistically. MATERIALS AND METHODS: 218 patients whose chief complaint was the extraction of the mandibular third molar were examined. The presence and absence of pericoronitis, age, sex, position of extraction site, angulation, impaction degree, position to the anterior border of mandibular ramus, distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of the mandibular third molar were assessed. Then the correlation of pericoronitis and the eruption state of the mandibular third molar were analyzed by Student's t-test and chi-square test. RESULTS: There was no correlation between Pericoronitis and age, sex, position of the mandibular third molar. The angulation(P=0.005), impaction degree(P=0.043), relation with anterior border of mandibular ramus(P=0.003), distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of the mandibular third molar(P<0.05) were correlated with pericoronitis. CONCLUSIONS: The occurrence of the pericoronitis can be predicted by the eruption state of the mandibular third molar such as angulation, impaction degree, relation with anterior border of mandibular ramus, distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of third molar.
Humans ; Molar ; Molar, Third* ; Pericoronitis* ; Tooth Cervix

OBJECTIVES: Pericoronitis was the most common indication for mandibular third molar surgery and there are no universally acceptable predictive criteria for pericoronitis occurrence. This study was designed to analyze the correlation of the pericoronitis and the eruption state of the mandibular third molar using panoramic radiographs statistically. MATERIALS AND METHODS: 218 patients whose chief complaint was the extraction of the mandibular third molar were examined. The presence and absence of pericoronitis, age, sex, position of extraction site, angulation, impaction degree, position to the anterior border of mandibular ramus, distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of the mandibular third molar were assessed. Then the correlation of pericoronitis and the eruption state of the mandibular third molar were analyzed by Student's t-test and chi-square test. RESULTS: There was no correlation between Pericoronitis and age, sex, position of the mandibular third molar. The angulation(P=0.005), impaction degree(P=0.043), relation with anterior border of mandibular ramus(P=0.003), distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of the mandibular third molar(P<0.05) were correlated with pericoronitis. CONCLUSIONS: The occurrence of the pericoronitis can be predicted by the eruption state of the mandibular third molar such as angulation, impaction degree, relation with anterior border of mandibular ramus, distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of third molar.
Humans ; Molar ; Molar, Third* ; Pericoronitis* ; Tooth Cervix

OBJECTIVE: This study aimed to (1) evaluate the effects of maxillary second and third molar eruption status on the distalization of first molars with a modified palatal anchorage plate (MPAP), and (2) compare the results to the outcomes of the use of a pendulum and that of a headgear using three-dimensional finite element analysis. METHODS: Three eruption stages were established: an erupting second molar at the cervical one-third of the first molar root (Stage 1), a fully erupted second molar (Stage 2), and an erupting third molar at the cervical one-third of the second molar root (Stage 3). Retraction forces were applied via three anchorage appliance models: an MPAP with bracket and archwire, a bone-anchored pendulum appliance, and cervical-pull headgear. RESULTS: An MPAP showed greater root movement of the first molar than crown movement, and this was more noticeable in Stages 2 and 3. With the other devices, the first molar showed distal tipping. Transversely, the first molar had mesial-out rotation with headgear and mesial-in rotation with the other devices. Vertically, the first molar was intruded with an MPAP, and extruded with the other appliances. CONCLUSIONS: The second molar eruption stage had an effect on molar distalization, but the third molar follicle had no effect. The application of an MPAP may be an effective treatment option for maxillary molar distalization.
Crowns ; Finite Element Analysis* ; Molar* ; Molar, Third