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Characteristics of bony changes and tooth displacement in the mandibular cystic lesion involving the impacted third molar.

Lee JH, Kim SM, Kim HJ, Jeon KJ, Park KH, Huh JK - J Korean Assoc Oral Maxillofac Surg (2014)

Bottom Line: Downward displacement was primarily observed in each group.Odontogenic keratocyst and ameloblastoma showed more aggressive growth pattern with higher rate of bony discontinuity and cortical bone expansion than in dentigerous cyst.However, when the third molar displacement and cortical bone absorption are observed, then odontogenic keratocyst or ameloblastoma should be considered.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral and Maxillofacial Surgery, Gangnam Severance Hospital, Yonsei University College of Dentistry, Seoul, Korea.

ABSTRACT

Objectives: The purpose of this retrospective study is to find the differentiating characteristics of cystic and cystic-appearing lesions that involve the impacted mandibular third molar by analyzing panoramic radiographs and computed tomography images, and to aid the preoperative diagnosis.

Materials and methods: Eighty-one patients who had a mandibular cystic or cystic-appearing lesion that involved impacted mandibular third molar and underwent cyst enucleation were included in the study. The preoperative panoramic radiograph and computed tomography findings were analyzed in accordance to the histopathologic type.

Results: Most of the cystic lesions containing the mandibular third molar were diagnosed as a dentigerous cyst (77.8%). The occurrence of mesio-distal displacement of the third molar was more frequent in the odontogenic keratocyst (71.4%) and in the ameloblastoma (85.7%) than in the dentigerous cyst (19.1%). Downward displacement was primarily observed in each group. Odontogenic keratocyst and ameloblastoma showed more aggressive growth pattern with higher rate of bony discontinuity and cortical bone expansion than in dentigerous cyst.

Conclusion: When evaluating mandibular cystic lesions involving the impacted mandibular third molar, dentigerous cyst should first be suspected. However, when the third molar displacement and cortical bone absorption are observed, then odontogenic keratocyst or ameloblastoma should be considered.

No MeSH data available.


Related in: MedlinePlus

Tooth displacement patterns on panoramic radiographs. Any position that did not deviate from the described standard was considered normal. A. a: Occlusal plane of the mesial teeth. b: The line parallel to (a), extending to the root tips of the second molar. c: The line perpendicular to (a) and tangent to the height of the distal contour of the second molar. d: The line parallel to (c) and located behind the length of the mesio-buccal width of the second molar. B. Downward displacement. C. Backward displacement. D. Back-upward displacement.
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Figure 1: Tooth displacement patterns on panoramic radiographs. Any position that did not deviate from the described standard was considered normal. A. a: Occlusal plane of the mesial teeth. b: The line parallel to (a), extending to the root tips of the second molar. c: The line perpendicular to (a) and tangent to the height of the distal contour of the second molar. d: The line parallel to (c) and located behind the length of the mesio-buccal width of the second molar. B. Downward displacement. C. Backward displacement. D. Back-upward displacement.

Mentions: Displacement of the IMTM was categorized by direction as diagnosed on panoramic radiographs. If the center of the third molar was positioned below the line passing through the root tips of the adjacent normal erupted second molar, then the displacement was categorized as downward. If the center of the third molar was positioned above the extended line of the occlusal plane, then the displacement was categorized as upward. When the third molar was displaced beyond the MD width of the adjacent second molar towards the distal side of the second molar, then the displacement was categorized as backward. In cases of missing, root resorption, or ectopic displacement of the mesially positioned molar teeth, the region was measured assuming normal posterior tooth eruption. Any position that did not deviate from these standards was considered normal.(Fig. 1)


Characteristics of bony changes and tooth displacement in the mandibular cystic lesion involving the impacted third molar.

Lee JH, Kim SM, Kim HJ, Jeon KJ, Park KH, Huh JK - J Korean Assoc Oral Maxillofac Surg (2014)

Tooth displacement patterns on panoramic radiographs. Any position that did not deviate from the described standard was considered normal. A. a: Occlusal plane of the mesial teeth. b: The line parallel to (a), extending to the root tips of the second molar. c: The line perpendicular to (a) and tangent to the height of the distal contour of the second molar. d: The line parallel to (c) and located behind the length of the mesio-buccal width of the second molar. B. Downward displacement. C. Backward displacement. D. Back-upward displacement.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4217264&req=5

Figure 1: Tooth displacement patterns on panoramic radiographs. Any position that did not deviate from the described standard was considered normal. A. a: Occlusal plane of the mesial teeth. b: The line parallel to (a), extending to the root tips of the second molar. c: The line perpendicular to (a) and tangent to the height of the distal contour of the second molar. d: The line parallel to (c) and located behind the length of the mesio-buccal width of the second molar. B. Downward displacement. C. Backward displacement. D. Back-upward displacement.
Mentions: Displacement of the IMTM was categorized by direction as diagnosed on panoramic radiographs. If the center of the third molar was positioned below the line passing through the root tips of the adjacent normal erupted second molar, then the displacement was categorized as downward. If the center of the third molar was positioned above the extended line of the occlusal plane, then the displacement was categorized as upward. When the third molar was displaced beyond the MD width of the adjacent second molar towards the distal side of the second molar, then the displacement was categorized as backward. In cases of missing, root resorption, or ectopic displacement of the mesially positioned molar teeth, the region was measured assuming normal posterior tooth eruption. Any position that did not deviate from these standards was considered normal.(Fig. 1)

Bottom Line: Downward displacement was primarily observed in each group.Odontogenic keratocyst and ameloblastoma showed more aggressive growth pattern with higher rate of bony discontinuity and cortical bone expansion than in dentigerous cyst.However, when the third molar displacement and cortical bone absorption are observed, then odontogenic keratocyst or ameloblastoma should be considered.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral and Maxillofacial Surgery, Gangnam Severance Hospital, Yonsei University College of Dentistry, Seoul, Korea.

ABSTRACT

Objectives: The purpose of this retrospective study is to find the differentiating characteristics of cystic and cystic-appearing lesions that involve the impacted mandibular third molar by analyzing panoramic radiographs and computed tomography images, and to aid the preoperative diagnosis.

Materials and methods: Eighty-one patients who had a mandibular cystic or cystic-appearing lesion that involved impacted mandibular third molar and underwent cyst enucleation were included in the study. The preoperative panoramic radiograph and computed tomography findings were analyzed in accordance to the histopathologic type.

Results: Most of the cystic lesions containing the mandibular third molar were diagnosed as a dentigerous cyst (77.8%). The occurrence of mesio-distal displacement of the third molar was more frequent in the odontogenic keratocyst (71.4%) and in the ameloblastoma (85.7%) than in the dentigerous cyst (19.1%). Downward displacement was primarily observed in each group. Odontogenic keratocyst and ameloblastoma showed more aggressive growth pattern with higher rate of bony discontinuity and cortical bone expansion than in dentigerous cyst.

Conclusion: When evaluating mandibular cystic lesions involving the impacted mandibular third molar, dentigerous cyst should first be suspected. However, when the third molar displacement and cortical bone absorption are observed, then odontogenic keratocyst or ameloblastoma should be considered.

No MeSH data available.


Related in: MedlinePlus