Anesthesia Flashcards
Q164 : It has been shown in several studies that Articaine provide better anesthesia than Lidocaine Explain?
It may be the unique chemical structure of articaine (its thiophene ring) that facilitate better diffusion of the anesthetic solution to the teeth. (Robertson et al. JADA - 2007)
Q165 : What alternative solution could be used in patients whose medical condition suggests caution in administering epinephrine - or levonordefrin- containing solutions for intraosseous anesthesia?
3% mepivacaine (Carbocaine, Polocaine). (Replogle et al, JADA 1999)
Q166 : Why would an intra-osseous injection fail?
1) Back pressure during injection
2) Not perforating the full depth of the cortical bone
3) In less than 10% of the cases, constricted cancellous spaces may limit the distribution of the solution around the apices of the teeth.
Q167 : Why there is a wide variation in the results of pain-related studies?
Pain is a subjective feeling and it can vary from one patient to the other.
Q168 : Which of the following supplementary injections provides the highest success rate for an Inferior Alveolar Nerve Block (IANB)?
Intra-osseous injection increases the success rate of IANB from 18% to 82% in mandibular molars with Irreversible pulpitis (Nusstein et al, JOE-2003) and from 42% to 90% in healthy mandibular molars (Dunbar et al, JOE - 1996)
Q169 : Does increasing the epinephrine concentration increases the success rate of inferior Alveolar Nerve Blocks (IANB)?
No
It has been shown by Dagher et al. (JOE-1997) and Wali et al (JOE - 2010) that increasing the concentration of epinephrine does not improve the success rate of IANB.
Q170 : Does preoperative administration of NSAID increase the success rate of inferior alveolar nerve blocks (ANB) in patients with inflamed pulp?
Yes
Noguera-Gonzalez et al. (IEJ-2013) showed that pre-op oral administration of ibuprofen significantly improved the efficacy of IANB in patients with symptomatic irreversible pulpitis. Ibuprofen increased the success rate of IANB from 36% to 72%. Similar results were showed by Akhlaghi et al. (JOE-2016) when ketorolac buccal infiltrations were administered to initiating treatment in patients diagnosed with symptomatic irreversible pulpitis.
In a recent systematic review by Nagendrababu et al. (JOE 2018), they have concluded that there is a positive effect of oral premedication of NSAIDs on IANB for treating patients with irreversible pulpitis.
Q171 : What are the possible clinical complications of intraosseous injection?
According to Replogle et al. (0000E - 1997)
1) Chances of swelling or exudate at the injection site
2) Tooth may feel high upon chewing
3) May cause transient increase in heart rate
4) The bone perforator can break
Q172 : Why there is a higher failure rate in inferior alveolar nerve block anesthesia in patients with irreversible pulpitis?
There have been four different reasons proposed as the cause of anesthetic failure in inferior alveolar nerve block:
1- The lowered pH of inflamed tissue, lowers the ionized form available in the nerve to achieve anesthesia (Hargreaves & Keiser, Endod Topic - 2002)
2- Inflamed tissue have altered resting potentials and decreased excitability thresholds (Wallace, et al, 0000-1985)
3- Increase in the Tetrodotoxin-resistant (TTXr) voltage gated Na Channels in inflamed pulp (Warren et al, JOE-2008) which can be resistant to the action of local anesthetics
4- Patients with preexisting hyperalgesia may be unable to tolerate any noxious input. (Hargreaves & Keiser, Endod Topic - 2002)
Q172 : Are two cartridges of anesthesia better than one cartridge in achieving pulpal anesthesia in maxillary teeth?
Yes
Increasing the volume of local anesthesia can extends the duration of pulpal anesthesia in maxillary teeth (Mikesell et al JOE - 2008)
Q174 : Does the volume of anesthetic solution affect the success rate of inferior alveolar nerve block (IANB) in patients with Irreversible pulpits?
Depends on the type of the anesthesia (articaine or lidocaine)
Fowler & Reader (JOE-2013) showed no significant difference between the two volumes of anesthetic in achieving successful pulpal anesthesia in inflamed pulps when lidocaine is used as the anesthetic solution. If Articane is used, however, increasing the volume has shown to provide a higher success rate in IANB in patient with Irreversible pulpitis increasing the success rate from 28% to 77% (Abazarpoor et al, JOE - 2015)
Q175 : What is the incidence of a transient heart rate increase in administration of an intraosseous injection of epinephrine containing solutions?
67% to 90% of patients will experience an increase in heart rate. Generally, the heart rate returns to baseline readings within four minutes in most patients. (Replogle et al, JADA 1999; Chamberlain et al, Gen Dent 2000; Stabile 0000E 2000)
Q176 : Does buccal infiltration improve the success rate of inferior alveolar nerve block (IANB)?
Depending on the type of anesthesia (Articaine or lidocaine)
Lidocaine buccal infiltration did not improve the success rate of of IANB (Foster et al. Anthes Prog - 2007). Articaine, however, improved the success rate of IANB in healthy patients and in cases with irreversible pulpitis, (Robertson et al, JADA-2007)
Q177 : It often recommended not to administer Articane as an inferior alveolar nerve block (IANB). Explain?
It is a common believe that Articaine injection as an inferior alveolar nerve block (IANB) may result in paresthesia. This was based on the work of Hass & Lennon (J Can Dent Assoc - 1995) who showed that in 143 reports of paresthesia not associated with surgery over a period of 20 years, paresthesia was reported most often following the injection of articaine and prilocaine. **Pogrel (J calif dental assoc-2007) **also reported that paresthesia rate is 5 times more with Articaine and Prilocaine. However, it should be noted that the level of evidence on these two studies is very weak. They were both retrospective studies with very little information on the cause of paresthesia. Some cases also reported paresthesia following lidocaine injection.
Several studies have used articaine as an inferior alveolar nerve block without any adverse effect noted (Abazarpoor et al, JOE-2015). Although it may be a common believe among clinicians, there is no strong evidence correlating administration of Articaine as an IANB and paresthesia.
Q178 : The success of intra-pulpal anesthesia depends on which of the following?
Type of anesthesia // Epinephrine conc // Volume of anesthesia // Pressure build up // All of the above
Brichfield & Rosenberg (JOE-1975) as well as VanGheluwe & Walton (0000E-1997) have shown that anesthesia produced by intra-pulpal injection was not the result of anesthetic solution but rather the pressure that is transmitted to the pulp by the solution in the syringe.
