Cortical integrity of the inferior alveolar canal as a predictor of paresthesia after third-molar extraction.
BACKGROUND
Paresthesia is a well-known complication of extraction of mandibular third molars (MTMs). The authors evaluated the relationship between paresthesia after MTM extraction and the cortical integrity of the inferior alveolar canal (IAC) by using computed tomography (CT).


METHODS
The authors designed a retrospective cohort study involving participants considered, on the basis of panoramic imaging, to be at high risk of experiencing injury of the inferior alveolar nerve who subsequently underwent CT imaging and extraction of the MTMs. The primary predictor variable was the contact relationship between the IAC and the MTM as viewed on a CT image, classified into three groups: group 1, no contact; group 2, contact between the MTM and the intact IAC cortex; group 3, contact between the MTM and the interrupted IAC cortex. The secondary predictor variable was the number of CT image slices showing the cortical interruption around the MTM. The outcome variable was the presence or absence of postoperative paresthesia after MTM extraction.


RESULTS
The study sample comprised 179 participants who underwent MTM extraction (a total of 259 MTMs). Their mean age was 23.6 years, and 85 (47.5 percent) were male. The overall prevalence of paresthesia was 4.2 percent (11 of 259 teeth). The prevalence of paresthesia in group 3 (involving an interrupted IAC cortex) was 11.8 percent (10 of 85 cases), while for group 2 (involving an intact IAC cortex) and group 1 (involving no contact) it was 1.0 percent (1 of 98 cases) and 0.0 percent (no cases), respectively. The frequency of nerve damage increased with the number of CT image slices showing loss of cortical integrity (P=.043).


CONCLUSIONS
The results of this study indicate that loss of IAC cortical integrity is associated with an increased risk of experiencing paresthesia after MTM extraction.
Park
Wonse
W
Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, Seoul, Korea.
Choi
Ji-Wook
JW
Kim
Jae-Young
JY
Kim
Bong-Chul
BC
Kim
Hyung Jun
HJ
Lee
Sang-Hwy
SH
D000293:Adolescent; D000328:Adult; D000539:Alveolar Process / Q000000981:diagnostic imaging* / Q000294:innervation; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging* / Q000294:innervation; D008340:Mandibular Nerve / Q000000981:diagnostic imaging; D008875:Middle Aged; D008964:Molar, Third / Q000601:surgery*; D010292:Paresthesia / Q000209:etiology*; D011183:Postoperative Complications; D011862:Radiography, Panoramic; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D019228:Tooth Crown / Q000000981:diagnostic imaging; D014081:Tooth Extraction / Q000009:adverse effects; D014092:Tooth Root / Q000000981:diagnostic imaging; D061221:Trigeminal Nerve Injuries; D055815:Young Adult