Fechney Angus, Clarke David E
School of Veterinary Science, Massey University, Palmerston North, New Zealand.
Dental Care for Pets, Melbourne, Australia.
J Vet Dent. 2025 Jan;42(1):41-47. doi: 10.1177/08987564241293188. Epub 2024 Oct 30.
Awareness among veterinarians has increased regarding the need for comprehensive pain relief, but many companion animal veterinarians do not administer regional analgesia pre-emptively during dental procedures. The middle mental nerve (MMN) block desensitizes the ipsilateral mandibular incisor and canine teeth as well as soft tissues rostral to the delivery site. There is little published information on the efficacy of the MMN block in dogs. The objective of this study was to determine injectate distribution within the mandibular canal using a radiopaque contrast media/methylene blue solution. Half a milliliter of solution was injected within the opening of the middle mental foramen using a standard hypodermic syringe and a 25G x 25 mm needle. The course of the injectate was traced both via computed tomography (CT) and, in some cadavers, gross dissection. Post-treatment CT revealed that in 90% of the cases, the contrast diffused at least as far caudally as the mesial root of the third premolar tooth. The injectate was not identified within the canal of 5% of cadaveric mandibles examined. Although the solution used diffused caudally within the mandibular canal when injected using recommended clinical techniques, this may not completely represent the extent of clinical effects experienced in live patients. This technique also confirmed that the needle does not need to be advanced into the mandibular canal to achieve adequate diffusion to at least the mesial root of the third premolar tooth.
兽医对全面缓解疼痛的必要性的认识有所提高，但许多伴侣动物兽医在牙科手术中并未预先进行区域镇痛。颏中神经（MMN）阻滞可使同侧下颌切牙和尖牙以及注射部位前方的软组织脱敏。关于犬类MMN阻滞疗效的公开信息很少。本研究的目的是使用不透射线的造影剂/亚甲蓝溶液确定下颌管内的注射剂分布。使用标准皮下注射器和25G×25 mm针头在颏中孔开口处注射半毫升溶液。通过计算机断层扫描（CT）并在一些尸体中通过大体解剖追踪注射剂的行程。治疗后CT显示，在90%的病例中，造影剂至少向尾侧扩散至第三前磨牙近中根处。在所检查的5%的尸体下颌骨管内未发现注射剂。尽管使用推荐的临床技术注射时，所用溶液在下颌管内向尾侧扩散，但这可能并不完全代表活体患者所经历的临床效果范围。该技术还证实，无需将针头推进下颌管内即可实现至少扩散至第三前磨牙近中根处的充分扩散。
