Primary and supplementary anesthetic efficacy of a modified two-step buccal infiltration of 4% articaine in mandibular molars with symptomatic irreversible pulpitis: a randomized clinical trial.

OBJECTIVES: To evaluate a modified two-step buccal infiltration (MBI) of 1.7 mL 4% articaine as primary or supplemental anesthesia in mandibular first and second molars diagnosed with symptomatic irreversible pulpitis (SIP). MATERIALS AND METHODS: One hundred and eight patients with SIP were randomly assigned to one of three groups (n = 36). They were given an inferior alveolar nerve block (IANB) of 2% lidocaine with 1:80.000 epinephrine or a primary MBI of 4% articaine with 1:100.000 epinephrine in the IANB and MBI groups, respectively. Patients in the IANB + MBI group received an IANB followed by an MBI. Pain levels during the injection, access cavity preparation, and initial filing were recorded on the Heft-Parker visual analog scale (HP-VAS). No or mild pain (HP-VAS ≤ 54) upon access cavity preparation and initial filing was considered a success. Chi-square and Kruskal-Wallis tests were used to analyze the data. RESULTS: MBI (77.8%) and IANB + MBI (94.4%) had both significantly higher success rates than IANB (50.0%) (P < .001). However, when the Bonferroni adjustment was applied, there was no statistically significant difference between the MBI and IANB + MBI techniques (P = .041 > .017). MBI was associated with significantly less injection pain than IANB (P < .001). CONCLUSIONS: Both primary and supplemental MBI with 4% articaine were superior to IANB with 2% lidocaine in mandibular first and second molars diagnosed with SIP. Further research may be needed to confirm the findings of this study. CLINICAL RELEVANCE: The findings of this study suggest that supplemental or primary MBI can be a clinically viable alternative to IANB, which has a relatively low success rate when managing mandibular molars diagnosed with SIP.

Preoperative oral use of Ibuprofen or dexamethasone may improve the anesthetic efficacy of an inferior alveolar nerve block in patients diagnosed with irreversible pulpitis.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Effect of premedication with ibuprofen and dexamethasone on success rate of inferior alveolar nerve block for teeth with asymptomatic irreversible pulpitis: a randomized clinical trial. Shahi S, Moktari H, Rahimi S, Yavari HR, Narimani S, Abdolrahmi M, Nezafati S. J Endod 2013;39(2):160-2. REVIEWER: John M. Nusstein, DDS, MS PURPOSE/QUESTION: To determine whether preoperative oral administration of ibuprofen (400 mg), dexamethasone (0.5 mg), or placebo (lactose) would improve the anesthetic success rate of an inferior alveolar nerve block in patients with molars diagnosed with asymptomatic irreversible pulpitis SOURCE OF FUNDING: University: Dental and Periodontal Research Center of Tabriz, Tabriz University of Medical Sciences, Tabriz, Iran TYPE OF STUDY/DESIGN: Randomized controlled trial LEVEL OF EVIDENCE: Level 2: Limited-quality, patient-oriented evidence STRENGTH OF RECOMMENDATION GRADE: Not applicable.

Maxillary Lateral Incisor Injection Pain Using the Dentapen Electronic Syringe.

INTRODUCTION: When patients express fear and anxiety about dentistry, 1 main source involves the administration of local anesthetic. The Dentapen (Septodont, Lancaster, PA) is a computer-controlled local anesthetic device that regulates the rate of anesthetic deposition to reduce pain associated with dental injections. The purpose of this study was to evaluate differences in perceived pain during the administration of local anesthesia of the maxillary lateral incisors using the ramp-up and continuous injection modes of the Dentapen. METHODS: This study used a randomized, controlled, double-blind, crossover, experimental design. The investigators randomly assigned the order of the teeth (#7 or #10) and the 2 delivery modes (continuous or ramp-up). Participants completed a Corah dental anxiety scale at each visit and were injected on 2 separate visits at least 2 weeks apart. After each injection, participants rated their perceived pain using a Heft-Parker visual analog scale at needle insertion, needle placement, and solution deposition. Repeated measures analysis of variance was used to determine differences in perceived pain between the 2 modes. RESULTS: The data from 116 participants were analyzed. The perceived pain at deposition with the ramp-up mode (mean = 51.98, standard deviation = 30.04) was less than the continuous mode (mean = 59.98, standard deviation = 36.28) although not statistically significant (F1230 = 2.569, P > .05). Clinically, the perceived pain with the ramp-up mode was in the mild range (<54 mm), whereas the mean perceived pain with the continuous mode was in the moderate/severe range (>54 mm). CONCLUSIONS: Further research should evaluate whether the ramp-up mode could be used to reduce the pain perceived with other dental injections.

Vickers hardness investigation of work-hardening in used NiTi rotary instruments.

A contributing mechanism for clinical failure of NiTi rotary instruments might be excessive work hardening. Vickers hardness was measured with 300 gm load near the flutes in three regions (D2-D4, D6-D10, and D14 towards the shank) for nine representative clinically used ProFile GT instruments that had been axially sectioned (10 measurements in each region). Consistent values could not be obtained at D1. Minimum hardness occurred at D2 to D4, with means from 313 to 324 (SD from 7 to 16). Maximum hardness with means ranging widely from 330 to 481 was found beyond D14. Mean hardness at D2 to D4 was 320 for an as-received ProFile instrument. Because a mean Vickers hardness of 326 has been reported for a shape-memory NiTi orthodontic wire product, it can be concluded that the NiTi instruments did not experience substantial work hardening at D2 to D4 during clinical use, in agreement with previous differential scanning calorimetric analyses.

SEM observations of nickel-titanium rotary endodontic instruments that fractured during clinical Use.

Numerous discarded ProFile GT, ProFile, and ProTaper nickel-titanium rotary instruments obtained from two graduate endodontic clinics were examined by scanning electron microscopy. These instruments had an unknown history of clinical use and had fractured or experienced considerable permanent torsional deformation without complete separation. The failure processes generally exhibited substantial ductile character, evidenced by a dimpled rupture fracture surface. Crack propagation at grain boundaries and cleavage surfaces indicative of transgranular fracture were observed for some specimens. It appeared that oxide particles from the manufacturing process served as nucleating sites for the microvoids, leading to dimpled rupture. A previously unreported fracture mode also was observed, in which crack propagation, approximately parallel to the local flute orientation, connected pitted regions on the surface. Combining present and previous scanning electron microscopy observations of clinically failed instruments, suggestions are offered for improving their fracture resistance.

Effect of drainage upon access on postoperative endodontic pain and swelling in symptomatic necrotic teeth.

The purpose of this retrospective study was to determine the effect of drainage upon access on postoperative endodontic pain and swelling in symptomatic necrotic teeth. One hundred twenty-four emergency patients participated and each had a clinical diagnosis of a symptomatic necrotic tooth with an associated periapical radiolucency. The occurrence of drainage upon access was timed and recorded. After endodontic treatment, patients received ibuprofen, acetaminophen with codeine (30 mg), and a 6-day diary to record pain, percussion pain, swelling, and number and type of pain medication taken. The majority of patients with symptomatic necrotic teeth had significant postoperative pain and required analgesic medication to manage this pain. Obtaining short-term drainage upon access (average of 1.85 min) did not significantly (p > 0.05) reduce pain, percussion pain, swelling, or the number of analgesic medications taken for symptomatic necrotic teeth with periapical radiolucencies.

Proposed role of embedded dentin chips for the clinical failure of nickel-titanium rotary instruments.

Discarded ProFile and ProTaper nickel-titanium rotary instruments, with unknown history of clinical use, were obtained from graduate endodontic clinics at Ohio State University and University of Texas Health Science Center at Houston Dental Branch. These discarded instruments and as-received instruments of both types were examined with a scanning electron microscope to investigate effects of clinical use and causes of failure. For used ProTaper instruments, dentinal debris was wedged mostly in narrow, radial, land-type regions and less on convex flute surfaces. For used ProFile instruments, dentinal debris was wedged mostly in the metal rollover and on concave flute surfaces. Used instruments of both types exhibited widened machining grooves, and elongated and stretched roll-over. Dentin chips were wedged in surface micro-cracks that appeared to propagate from original machining flaws and widen during in vivo root canal preparation. From our observational study, wedged dentinal deposits seem to play a pivotal role for clinical failure of these instruments.

Comparison of preoperative pain and medication use in emergency patients presenting with irreversible pulpitis or teeth with necrotic pulps.

OBJECTIVE: This retrospective study compared differences in preoperative pain and medication use in patients with moderate to severe pain who sought emergency endodontic care for teeth with irreversible pulpitis and for symptomatic teeth with necrotic pulps. STUDY DESIGN: A total of 323 patients seeking emergency endodontic treatment completed questionnaires regarding their biographical information, pain, pain history, and medications. Teeth were tested for vitality, mobility, percussion, and palpation pain. Lymphadenopathy was also evaluated. RESULTS: Patients with irreversible pulpitis waited significantly (P <.05) longer before seeking emergency care (9 days vs 4 days) than patients with symptomatic teeth with necrotic pulps. No differences (P >.05) were found between the groups in terms of analgesic or antibiotic use and pain relief from preoperative narcotic medications. Nonnarcotic analgesics were reported to significantly reduce pain more often in patients with symptomatic teeth with necrotic pulps. There were sex differences in the group of patients with irreversible pulpitis: More women than men were taking analgesic medications and, in the group having symptomatic teeth with necrotic pulps, more men than women reported pain relief from their analgesic medications. CONCLUSION: Patients with irreversible pulpitis wait longer to seek emergency treatment. A majority (81%-83%) of emergency patients with moderate to severe pain will have taken some type of medication(s) to help control their pain, and more women than men with irreversible pulpitis will take an analgesic. By taking their preoperative medication(s), this group of patients will get relief 62% to 65% of the time; furthermore, more men than women with symptomatic teeth with necrotic pulps will experience pain relief.

Effectiveness of 20% benzocaine as a topical anesthetic for intraoral injections.

The use of topical anesthetics has been advocated prior to the administration of various types of anesthetic injections. Reported results have varied between studies. The purpose of this study was to compare the effectiveness of 20% benzocaine in reducing the pain of needle insertion during maxillary posterior and anterior infiltration and inferior alveolar nerve block injections. In this retrospective study, 1080 patients received 2336 injections using a 27-gauge needle. Topical anesthetic was applied prior to 720 of the injections. Patients rated pain of needle insertion using a 0-4 pain scale. Logistic regression analysis showed no differences in pain ratings between topical and no topical groups for the inferior alveolar nerve block and posterior maxillary infiltration injections. The use of topical anesthetic did reduce the pain of needle insertion with the maxillary anterior injections (P = .0041).

Local anesthesia strategies for the patient with a "hot" tooth.

Attaining local anesthesia for the treatment of teeth diagnosed with irreversible pulpitis ("hot" tooth) can be a challenge. This article looks at the strategies a dentist can use to help achieve adequate pulpal anesthesia for the patient, thereby eliminating or reducing treatment pain.

Micro-XRD and temperature-modulated DSC investigation of nickel-titanium rotary endodontic instruments.

OBJECTIVES: Employ Micro-X-ray diffraction and temperature-modulated differential scanning calorimetry to investigate microstructural phases, phase transformations, and effects of heat treatment for rotary nickel-titanium instruments. METHODS: Representative as-received and clinically used ProFile GT and ProTaper instruments were principally studied. Micro-XRD analyses (Cu Kalpha X-rays) were performed at 25 degrees C on areas of approximately 50 microm diameter near the tip and up to 9 mm from the tip. TMDSC analyses were performed from -80 to 100 degrees C and back to -80 degrees C on segments cut from instruments, using a linear heating and cooling rate of 2 degrees C/min, sinusoidal oscillation of 0.318 degrees C, and period of 60s. Instruments were also heat treated 15 min in a nitrogen atmosphere at 400, 500, 600 and 850 degrees C, and analyzed. RESULTS: At all Micro-XRD analysis regions the strongest peak occurred near 42 degrees , indicating that instruments were mostly austenite, with perhaps some R-phase and martensite. Tip and adjacent regions had smallest peak intensities, indicative of greater work hardening, and the intensity at other sites depended on the instrument. TMDSC heating and cooling curves had single peaks for transformations between martensite and austenite. Austenite-finish (A(f)) temperatures and enthalpy changes were similar for as-received and used instruments. Heat treatments at 400, 500 and 600 degrees C raised the A(f) temperature to 45-50 degrees C, and heat treatment at 850 degrees C caused drastic changes in transformation behavior. SIGNIFICANCE: Micro-XRD provides novel information about NiTi phases at different positions on instruments. TMDSC indicates that heat treatment might yield instruments with substantial martensite and improved clinical performance.