Intraosseous injection or inferior alveolar nerve block for third molar surgery?

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Effective local anaesthesia is important for undertaking third molar surgery and a number of anaesthetic agents (Dental Elf – 8th Feb 2021) and techniques (Dental Elf – 24th Jan 2022) are available including the conventional inferior alveolar nerve block, supraperiosteal/infiltration, Gow-Gates, Vazirani-Akinosi, intraligamentary, and intraosseous injections.

The aim of this review was to compare the anaesthetic efficacy of intraosseous injection and conventional inferior alveolar nerve block in mandibular third molar surgery.


A protocol for the review was registered in the PROSPERO database. Two reviewers searched the Medline/PubMed, Scopus and Web of Science databases for randomised controlled trials (RCTs) comparing intraosseous injection with inferior alveolar nerve block (INAB) for mandibular third molar surgery that were published in English. Data was extracted and quality assessment was undertaken by two reviewers using the Cochrane risk-of-bias tool for RCTs (RoB 2.0). Outcome measures included onset of anaesthesia, success of anaesthetic technique, pain during injection of anaesthesia, pain during surgery, and duration of anaesthesia. Risk ratio (RR) and mean difference (MD) with 95% confidence intervals (CI) were used to analyse out- comes for binary and continuous variables.


  • 4 RCTs of split mouth design involving a total of 121 patients (242 third molars) were included.
  • Articaine was used for the intraosseous injection and IANB.
  • The intraosseous injection was delivered by the same computerised delivery instrument in all 4 studies although injection sites differed.
  • None of the 4 studies were at low risk of bias will all having some concerns.
  • Meta-analyses found no significant differences between the two techniques for the outcomes assessed (see table).
Outcome No. of studies  
Onset of anaesthesia 3 MD = 45.06 secs (95%CI; 146.18 to 56.05secs)
Success of anaesthetic technique 3 RR = 0.80 (95%CI; 0.40 to 1.58)
Pain during injection 4 MD = – 0.11 (95%CI; – 1.28 to 1.07)
Pain during surgery 4 MD = 0.18 (95%CI; – 1.18 to 1.54)
Duration of anaesthesia 3 MD = 56.34 mins (95%CI; 70.72 to 41.9mins)


The authors concluded: –

The results of this study suggested that the intraosseous injection provided profound anaesthesia for mandibular third molar surgery (MTMS). The short duration of anaesthesia using the intraosseous technique might be pleasant for patients because it helps to patients regain sensation earlier than the conventional IANB. Thus, intraosseous injection could be a potential alternative to IANB for dental procedures, including MTMS.


While the authors have searched 3 large databases restricting the inclusion to RCTs published in English may have excluded some relevant studies.  Only 4 RCTs were included, and these were from just two countries (Thailand, Turkey) and the sample sizes are small. The authors also note that although a number of intraosseous delivery devices are available all 4 included studies used the same device. A recent review of anaesthetic techniques for mandibular posterior teeth with symptomatic irreversible pulpitis (Dental Elf – 24th Jan 2022) suggested that Vazirani-Akinosi nerve block, intraosseous injection and buccal infiltration with IANB were the most effective techniques although the supporting evidence was considered to be of very low to low quality. Future studies should be of appropriate size, well conducted, use common outcome sets and be reported in line with SPIRIT and CONSORT guidelines .


Primary Paper

Kumar K, Bhattarai BP, Subedi S. Comparison of anaesthetic efficacy of intraosseous injection with conventional inferior alveolar nerve block in mandibular third molar surgery: a systematic review and meta-analysis. Oral Surg Oral Med Oral Pathol Oral Radiol. 2022 Feb;133(2):e33-e42. doi: 10.1016/j.oooo.2021.07.020. Epub 2021 Jul 31. PMID: 34511344.

Review protocol on PROSPERO

Other references

Dental Elf – 8th Feb 2021

Third molar extractions: Which anaesthetic solution for the best pain control?

Dental Elf – 24th Jan 2022

Anaesthetic techniques for mandibular posterior teeth with symptomatic irreversible pulpitis


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