Title Administration of an Inferior Alveolar Nerve Block in the Region of a Developing Third-Molar May Lead to Third-Molar Agenesis
Clinical Question In healthy children receiving routine oral care, can administration of local anesthesia via a inferior alveolar nerve block cause agenesis of mandibular third-molars?
Clinical Bottom Line An inferior alveolar nerve block in the region of a developing third-molar may lead to third-molar agenesis; however, more studies with larger patient groups need to be conducted in order to verify the results of this study, show causation, and ultimately derive applicability from this knowledge.
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
23543693Swee/2013220 patients 7 to 12 years old who had received or not received an IANB before the age of 6.Retrospective Records Review
Key resultsThe patient group of 220 yielded 439 observable sites for possible mandibular third-molar development. The control group (sites that had not received an IANB) consisted of 376 sites while the test group (sites that had received an IANB) consisted of 63 sites. Of the control group 7 sites never developed a third-molar (1.9%), whereas 5 sites from the test group (sites that had received an IANB) never developed a third-molar (7.9%). With a confidence interval of 95% (1.37-13.38) and a P value of 0.013 this study showed a statistically significant difference between the two groups.
Evidence Search “inferior alveolar nerve block third molar agenesis”
Comments on
The Evidence
Validity: The validity level of this study is mediocre at best. The overall number of participants is high; however, the number of sites observed in the test group is relatively low. Both groups are similar at the beginning of the study and are treated equally. This study involves observing radiographs of participants, so recall bias is negated and compliance is not a factor. Research in this area is relatively new, and this may be the first study conducted on this topic. Larger and more numerous studies need to be conducted in order to verify the results of this study.
Applicability At this time there is not enough research to confidently state that inferior alveolar nerve blocks cause third-molar agenesis. There does seem to be some correlation between the two events according to this study. There may come a time where research may suggest that there is causation involved here, and that mechanism could be used in order to actively cause third-molar agenesis in patients who are determined to be good candidates for the procedure.
Specialty (General Dentistry) (Oral Surgery) (Pediatric Dentistry)
Keywords Inferior alveolar nerve block, mandibular nerve block, third-molar, agenesis
ID# 2684
Date of submission 03/18/2014
E-mail lalanik@livemail.uthscsa.edu
Author Khurram Lalani
Co-author(s)
Co-author(s) e-mail
Faculty mentor Richard B. Magness, DDS
Faculty mentor e-mail MagnessR@uthscsa.edu
   
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
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Comments and Evidence-Based Updates on the CAT
(FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs)
None available