Morphologic and hemodynamic analysis of dental pulp in dogs after molar intrusion with the skeletal anchorage system.
BACKGROUND
We have successfully treated skeletal open bite by intruding posterior teeth with the skeletal anchorage system. Our aim in this study was to morphologically and hemodynamically evaluate the changes in pulp tissues when molars are radically intruded.


METHODS
The mandibular fourth premolars of 9 adult beagle dogs were divided into 3 groups: a sham operated group (n = 6, 3 dogs), 4-month intrusion group (n = 6, 3 dogs), and a further 4-month retention group (n = 6, 3 dogs). We evaluated the morphological changes of the pulp and dentin-the amount of vacuolar degeneration in the odontoblast layer, the predentin width and nervous continuity in the pulp tissue, and the pulpal blood-flow response evoked by electrical stimulation in the dental pulp.


RESULTS
Extreme molar intrusion with the skeletal anchorage system caused slight degenerative changes in the pulp tissue, followed by recovery after the orthodontic force was released. Circulatory system and nervous functions were basically maintained during the intrusion, although a certain level of downregulation was observed. These morphologic and functional regressive changes in the pulp tissue after molar intrusion improved during the retention period.


CONCLUSIONS
Histologic changes and changes in pulpal blood flow and function are reversible, even during radical intrusion of molars.
Konno
Yuichi
Y
Division of Orthodontics and Dentofacial Orthopedics, Department of Oral Health and Development Sciences, Graduate School of Dentistry, Tohoku University, Sendai, Japan. yuuichi@mail.tains.tohoku.ac.jp
Daimaruya
Takayoshi
T
Iikubo
Masahiro
M
Kanzaki
Reiko
R
Takahashi
Ichiro
I
Sugawara
Junji
J
Sasano
Takashi
T
D000818:Animals; D003782:Dental Pulp / Q000098:blood supply* / Q000294:innervation / Q000473:pathology; D004285:Dogs; D004558:Electric Stimulation; D005260:Female; D017078:Laser-Doppler Flowmetry / Q000295:instrumentation / Q000379:methods; D008963:Molar / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000294:innervation; D024343:Open Bite / Q000628:therapy*; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation / Q000379:methods*; D010865:Pilot Projects; D011859:Radiography; D015203:Reproducibility of Results; D014087:Tooth Movement Techniques / Q000009:adverse effects* / Q000379:methods