Present status and future directions - Mechanisms and management of local anaesthetic failures

Effect of preemptive use of a nonsteroidal anti-inflammatory drug and a corticosteroid on the efficacy of inferior alveolar nerve blockade and postoperative pain control in endodontic treatment of molars with symptomatic pulpitis: A randomized double-blind placebo-controlled clinical trial

AIM

The anaesthetic success rate of an inferior alveolar nerve block (IANB) in mandibular molars with irreversible symptomatic pulpitis can be low, and postoperative pain control in teeth with this diagnosis can be challenging. This study aimed to evaluate the influence of preemptive use of dexamethasone and oral potassium diclofenac on the success of IANB. The influence of these drugs on the intensity of postoperative pain was assessed as a secondary outcome.

METHODOLOGY

Eighty-four patients with mandibular molars diagnosed with irreversible symptomatic pulpitis recorded preoperative pain intensity using a cold thermal test and a modified Numerical Rating Scale (mNRS). Sixty minutes before the anaesthetic procedure, patients were randomly assigned to one of three groups based on the medication they received: dexamethasone (4 mg), diclofenac potassium (50 mg), or placebo. All patients received IANB with 4% articaine (1:200 000 epinephrine), and 15 min later, they were evaluated for pain intensity using the cold thermal test. Anaesthetic success was analysed. The pain intensity was then recorded, and endodontic treatment and provisional restoration of the tooth were executed in a single session. Patients were monitored for 6, 12, 24, 48 and 72 h using the mNRS to assess the intensity of postoperative pain.

RESULTS

There was a statistically significant increase in anaesthetic success when 4 mg dexamethasone (39.3%) or 50 mg diclofenac potassium (21.4%) was used compared to the placebo group (3.6%) (p < .001), with no significant difference between the two drugs. Regarding postoperative pain, dexamethasone was superior to placebo at 6 h (p < .001), with diclofenac having an intermediate behaviour, not differing between dexamethasone and placebo (p > .05). There was no significant difference amongst the groups at 12 h (p > .05). At 24, 48 and 72 h, the effectiveness of dexamethasone and diclofenac were comparable, and both were superior to placebo (p < .001).

CONCLUSION

The use of dexamethasone or diclofenac potassium was favourable in terms of increasing the success rate of inferior alveolar nerve block in cases of mandibular molars with irreversible symptomatic pulpitis and decreased the occurrence of postoperative pain when compared to the use of a placebo.

Expression patterns of mechanosensitive ion channel PIEZOs in irreversible pulpitis

BACKGROUND

Mechanosensitive ion channel PIEZOs have been widely reported to involve inflammation and pain. This study aimed to clarify expression patterns of PIEZOs and their potential relations to irreversible pulpitis.

MATERIALS AND METHODS

Normal pulp tissues (n = 29) from patients with impacted third molars and inflamed pulp tissues (n = 23) from patients with irreversible pulpitis were collected. Pain levels were assessed using a numerical rating scale. PIEZO expressions were measured using real-time PCR and then confirmed using GEO datasets GSE77459, immunoblot, and immunohistochemistry staining. Correlations of PIEZO mRNA expression with inflammatory markers, pain markers, or clinical pain levels were evaluated using Spearman's correlation analysis. Univariate analysis was conducted to analyze PIEZO expressions based on pain description and clinical examinations of cold test, percussion, palpation, and bite test.

RESULTS

Compared with normal pulp tissues, mRNA expression levels of PIEZO1 were significantly increased in inflamed pulp tissues, while PIEZO2 was significantly decreased, which was further confirmed in GSE77459 and on a protein and histological level. The positive correlation of the mRNA expression levels between PIEZO1 and inflammatory markers, as well as between PIEZO2 and pain markers, was verified. PIEZO2 expression was also positively correlated with pain levels. Besides, irreversible pulpitis patients who reported continuous pain and who detected a positive response to cold stimulus exhibited a higher expression level of PIEZO2 in the inflamed pulp tissues. By contrast, patients reporting pain duration of more than one week showed a higher expression level of PIEZO1.

CONCLUSIONS

This study demonstrated the upregulation of PIEZO1 and the downregulation of PIEZO2 in irreversible pulpitis and revealed the potential relation of PIEZO1 and PIEZO2 to inflammation and pain. These findings suggested that PIEZOs might play critical roles in the progression of irreversible pulpitis and paved the way for further investigations aimed at novel therapies of irreversible pulpitis by targeting PIEZOs.

The use of medicaments in the management of symptomatic irreversible pulpitis: A community-based cohort study

AIM

To investigate patient outcomes from either pulpotomy or pulpectomy for the management of symptomatic irreversible pulpitis, with and without application of antibiotic/corticosteroid pastes in urgent primary dental care settings in the United Kingdom.

METHODOLOGY

All patients receiving intervention for symptomatic irreversible pulpitis in three different primary care settings were invited to participate. Pre-operatively, data regarding patients' numerical ratings scale (NRS), pain score (0-10), analgesic use, oral-health impact profile-14 (OHIP-14) and need for time away from work were collected. For 7 days post-operatively, participants recorded their NRS pain score, global rating of change score, medication use and their ability to work. Analysis used a mixed-effects model with post hoc Tukey's multiple comparisons test for continuous data and chi-squared or Fisher's exact test for categorical data. To test the effect of the corticosteroid/antibiotic paste, pulpectomy and pulpotomy groups were combined following Mantel-Haenszel stratified analysis or a weighted average of the difference between pulpotomy and pulpectomy with and without the use of corticosteroid/antibiotic paste. A binary composite score was constructed using pre- and post-operative data, whereby overall treatment success was defined as: (i) patients did not return for treatment due to pain by day seven; (ii) at day three, there was a 33% (or 2-points) reduction in NRS pain score; (iii) there was a change score of +3 in global rating; (iv) the patient was no longer using analgesia and able to return to work.

RESULTS

Eighty-five participants were recruited, with 83 completing follow up. Overall treatment success was 57%, with 25% of participants returning for more treatment due to inadequate pain relief. Overall treatment success did not differ between the two groups (p = .645), although patients self-reported greater improvement with an antibiotic/corticosteroid dressing for global rating of change (p = .015).

CONCLUSIONS

This study identified limited evidence of improved outcomes using antibiotic/corticosteroid dressings in the management of symptomatic irreversible pulpitis in the emergency setting. Further clinical research is needed to understand if these medications are beneficial in affording pain relief, above that of simple excision of irreversibly inflamed pulp tissue.

Systemic Corticosteroid Uses in Endodontics-Part 2: Enhancing the Success of Local Anesthesia

INTRODUCTION

Chronic inflammation in irreversible pulpitis leads to heightened sensitivity of nociceptive receptors, resulting in persistent hyperalgesia. This poses significant challenges in achieving effective anesthesia for patients with irreversible pulpitis. Various anesthetic techniques and pharmacological approaches have been employed to enhance the success of local anesthesia. Recently, the preemptive use of anti-inflammatory agents, specifically corticosteroids, has gained attention and shown promising results in randomized controlled trials. This systemic review and meta-analysis aimed to evaluate the impact of systemically administered corticosteroids on enhancing anesthetic success in patients undergoing endodontic treatment.

METHODS

A comprehensive search was conducted across multiple databases including PubMed, Cochrane Library, Embase, Scopus, Dentistry & Oral Science, and ProQuest. Additionally, the references of primary studies and related systematic reviews were manually searched for additional relevant publications. The primary outcome assessed was the success of anesthesia, and the effect measure was risk ratio using the random-effects inverse variance method. Statistical significance was set at P < .05. The certainty of the evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation approach.

RESULTS

Twelve studies involving 917 participants were analyzed to determine the frequency of successful anesthesia. The corticosteroid group demonstrated a significantly higher number of patients achieving successful anesthesia (risk ratio = 1.66; 95% confidence interval, 1.34-2.06;P < .00001). However, heterogeneity within the pooled data analysis was observed (I2 = 57%, P = .007).

CONCLUSIONS

Moderate certainty evidence indicates that preemptive use of systemic corticosteroids enhances the success of local anesthesia, specifically inferior alveolar nerve block, in cases of irreversible pulpitis.

Efficacy of articaine anesthesia with needle-free/Comfort-in method and conventional needle injection in dental patients with irreversible pulpitis: a randomized clinical trial

OBJECTIVE

To assess the anesthetic efficacy of articaine with the needle-free/Comfort-in™ method compared to the conventional needle method. To assess pain during anesthesia application, onset of anesthesia and patient`s self-reported quality of life-related to oral health after the dental emergency appointment.

MATERIALS AND METHODS

This parallel, randomized clinical trial was conducted by a single operator/dentist in the state of Maranhao, northeast of Brazil. Included participants were adult dental patients with one molar (maxillary) or premolar (maxillary or mandibular) tooth diagnosed with symptomatic irreversible pulpitis. The primary outcome was the anesthetic efficacy, measured using a combination of electrical and cold pulp tests (cold + EPT) and the Numerical Rating Scale (NRS). Secondary outcomes were pain during anesthesia application, onset of anesthesia, and patient`s quality-of-life (measured with the OHIP-14).

RESULTS

62 patients were randomized in the anesthesia needle-free group and Comfort-in group (34.26 ± 10.786 × 33.29 ± 8.399 years old, respectively). The group of patients in the Comfort-in group had 71.0% success. Patients from the Comfort-in group reported statistically lower pain during the anesthesia application than patients from the conventional group (2.13 ± 2.172 × 6.03 ± 3.146 NRS scores, respectively) as well as immediately after the anesthetic procedure. Patients self-reported negative impact in quality of life was similar between groups before (p > 0.05) and after (p > 0.05) the dental emergency.

CONCLUSIONS

Comfort-in™ had similar efficacy to the conventional needle method.

CLINICAL RELEVANCE

This trial showed that it is possible to anesthetize patients with tooth pulpits without using needles to provide comfort mainly to anxious patients.

4-Year Pulp Survival in a Randomized Trial on Direct Pulp Capping

INTRODUCTION

This study aimed to assess pulp survival in a randomized trial on pulp lavage in adult nonpainful posterior teeth with carious pulp exposure. The treatment included complete caries excavation, direct pulp capping with mineral trioxide aggregate, and immediate restoration with composite resin.

METHODS

Fluid was collected from the pulp wound to assess matrix metalloproteinase-9 (MMP-9) and total protein values. Before pulp capping, cavities were randomly (block randomization, n = 48) washed with a physiological saline or a sodium hypochlorite solution (2.5% NaOCl). Treatment outcome was assessed clinically (cold test) and radiographically after at least 1 year and again after at least 3 years. Painful failures were differentiated from nonpainful failures. Pulp survival was estimated using the Kaplan-Meier method including 95% confidence intervals (CIs) up to 1500 days.

RESULTS

From the 96 patients originally enrolled, 73 individuals could be followed continuously. The clinical observations indicated a beneficial and sustained effect of pulp lavage with 2.5% NaOCl over a control treatment with physiological saline solution on estimated pulp survival 1500 days postintervention, with 7% (95% CI, 1%-40%) in the saline group versus 55% (95% CI, 30%-100%) in the NaOCl group. High MMP-9/total protein values in pulpal fluid collected from the exposed site indicated early and painful treatment failures yet were not associated with failures that occurred more than 250 days after intervention.

CONCLUSIONS

The low 4-year success rates reported here challenge the concept of direct pulp capping in the cases that were included. NaOCl lavage did not only increase the survival of affected pulps substantially but also particularly diminished painful failures (33% in the NaOCl group vs 62% in the saline group). The lack of the predictive value of MMP-9 assessments beyond early treatment failures points to inflammatory states of the pulp tissue under deep caries, which are not related to neutrophil infiltration.

Pulpal anesthesia of maxillary first molars using 4% articaine infiltration in patients with symptomatic irreversible pulpitis: a randomized controlled clinical trial

OBJECTIVES

This study aimed to compare the anesthetic efficacy of 1.8 mL (one cartridge) and 3.6 mL (two cartridges) buccal infiltration and buccal plus palatal infiltration of 4% articaine in maxillary first molar teeth with symptomatic irreversible pulpitis.

MATERIALS AND METHODS

This randomized single-blind clinical trial was conducted on 45 patients with symptomatic irreversible pulpitis of maxillary first molars (Trial Registration No: IRCT2015011020238N2_2015). The patients were randomly divided into three groups (n = 15) for buccal infiltration of 1.8 mL articaine plus 1:100,000 epinephrine (group 1), buccal infiltration of 3.6 mL articaine (group 2), and buccal infiltration of 1.8 mL articaine plus palatal infiltration of 0.5 mL articaine (group 3). The pain intensity was measured by the Heft-Parker visual analog scale (VAS) during injection and during access cavity preparation. No pain or mild pain during treatment was considered as successful anesthesia. Data were analyzed by the Tukey's post hoc test.

RESULTS

The three groups had a significant difference in frequency of the perceived pain during injection (P = 0.01). A higher volume of 4% articaine and injection of articaine in both buccal and palatal sides provided a significantly higher anesthesia success rate (P = 0.049 and P < 0.01, respectively). The highest success rate was recorded in group 3 (93.33%) followed by group 2 (80%) and then group 1 (53.33%).

CONCLUSIONS

Increasing the administered volume of 4% articaine with 1:100,000 epinephrine and addition of palatal infiltration to buccal infiltration of articaine can significantly increase the success of anesthesia in maxillary first molars with symptomatic irreversible pulpitis.

CLINICAL RELEVANCE

Achieving deep anesthesia in teeth with irreversible pulpitis is a critical parameter in management of patients who are in urgent need of root canal treatments.

Inferior Alveolar Nerve Block Success of 2% Mepivacaine versus 4% Articaine in Patients with Symptomatic Irreversible Pulpitis in Mandibular Molars: A Randomized Double-Blind Single-Centre Clinical Trial

AIM

To assess inferior alveolar nerve block (IANB) success of 2% mepivacaine (Scandonest 2%, Septodont, France) and 4% articaine (Septanest 4%, Septodont) in patients with symptomatic irreversible pulpitis (SIP) in mandibular molars during access cavity preparation and instrumentation.

METHODOLOGY

Three hundred and thirty patients with moderate-to-severe pain in mandibular molars with SIP randomly received either 3.6 mL 2% mepivacaine hydrochloride with 1:100 000 adrenalin or 3.4mL 4% articaine hydrochloride with 1:100 000 adrenalin (n=165). Intraoperative pain (IOP) intensity was assessed during access cavity preparation and canal instrumentation using 11-point numerical rating scale (NRS). Overall success was considered if the patient felt no-to-mild pain without the need of supplemental anaesthesia throughout treatment; the incidence of need for supplemental anaesthesia was also recorded. Data were statistically analyzed using Mann Whitney U and Chi² (χ² ) tests. Relative risk (RR) and 95% confidence interval (CI) of anaesthetic failure was calculated. The effect of predisposing factors on outcome variables was assessed using multivariable regression analyses. None of the participants reported any adverse effects.

RESULTS

Baseline variables were balanced between groups (p>0.05). The IOP intensity during access cavity preparation and canal instrumentation was similar for both groups (p>0.05). IOP intensity was associated with preoperative pain intensity and tooth type (p<0.05). Overall anaesthetic success rate was 35.8% for mepivacaine and 41.2% for articaine (p>0.05) with a relative risk of failure [95%CI] 1.09 [0.92, 1.30]. The need for supplemental anaesthesia occurred 43.6% and 38.2% with mepivacaine and articaine respectively (p>0.05; RR [95%CI]: 1.14 [0.88, 1.48]). Preoperative pain level and age were associated with the need for supplemental anaesthesia.

CONCLUSIONS

2% mepivacaine and 4% articaine demonstrate similar IANB success rates for mandibular molars with SIP. Intraoperative pain experience during endodontic treatment can be associated with preoperative pain, tooth type and age.