5.Finding the sealant ceiling

The purpose of this study was to investigate the depths of penetration of a calcium silicate-based sealer in dentinal tubules by using three different obturation methods. Extracted human permanent anterior teeth (n=100) were endodontically prepared and divided equally into one control and three experimental groups: CPoint single cone, gutta-percha single cone, gutta-percha vertical condensation: all with a calcium silicate-based sealer and calcium indicator Fluo-3. A CPoint single cone group with a calcium indicator Fluo-3 without sealer was the control. The tooth roots in each group were cross-sectioned, and the surfaces were examined under confocal laser scanning microscopy at x10 and x20 magnifications. The sealer penetration depths were measured at their maximum depths and at four circumferential depths (12, 3, 6, and 9 o’clock) by using fluorescence. The pressure derived from hygroscopic expansion of CPoint or warm vertical condensation did not enhance penetration depths of the calcium silicate-based sealer. Sealer penetration into the dentinal tubules occurred independently of the obturation technique.

Jeong JW et al. Dentinal tubule penetration of a calcium silicate-based root canal sealer with different obturation methods. J Endodontics 2017 43: 633-637

Q Which obturation technique ensured the greatest sealer penetration into dentinal tubules?
A Gutta-percha single cone
B Gutta-percha vertical condensation
C CPoint single cone
D All of the above were equal as sealer penetration was independent of technique

6.Retreating can be a pain

The intensity and duration of postoperative pain after the removal of root canal filling material in retreatment procedures of upper incisor teeth with chronic apical periodontitis, using different techniques, was assessed in this research. Patients (n=135) requiring such retreatment were studied by assignment to one of three groups according to the method of old canal filling material removal: Group 1, hand files, Group 2, ProTaper universal retreatment instruments, Group 3, Reciproc instruments. Teeth were then medicated with calcium hydroxide and sealed using temporary filling material. The presence of postoperative pain was assessed after 6, 12, 24, 48 and 72h, 7 and 10 days. In all time intervals, except for 72h, 7 days and 10 days, Group 1 participants reported more intense postoperative pain than those in the other two groups in which there were no differences at any time interval. In all groups, the intensity of postoperative pain decreased over time. Hand files caused greater postoperative pain compared to the ProTaper retreatment and Reciproc files.

Topcuoglu HS, Topcuoglu G. Postoperative pain after the removal of root canal filling material using different techniques in teeth with failed root canal therapy: a randomized clinical trial. Acta Odontologica Scandinavica 2017 75: 249-254.

Q If you had to retreat a root filled upper incisor tooth with chronic apical periodontitis which of the following would cause your patient less postoperative pain?
A Hand file
B Reciproc
C ProTaper
D B and C

7.Percentage plus

What effect do two different concentrations of sodium hypochlorite (NaOCl) solution have on postoperative pain following single-visit root canal treatment? The method in this study involved 122 patients who had mandibular molars with irreversible pulpitis and who were randomly divided into two groups using either 2.5% or 5.25% NaOCl during root canal instrumentation. Rotary instruments were used and all root canals were filled in one visit. The patients that had 5.25% NaOCl reported significantly lower postoperative pain compared to the other group during the first 72 hours following treatment; however, there was no significant difference in pain felt by the patients during the rest of the study period, i.e. 4-7 days following treatment when a 4-level pain categorisation method was used. When the two-level pain categorisation method was used, patients who had 5.25% NaOCl reported significantly less pain for the first three days after treatment. The number of analgesics taken by patients who had 2.5% NaOCl was significantly higher than that taken by patients who had 5.25% NaOCl.

Farzaneh S et al. Effect of two different concentrations of sodium hypochlorite on postoperative pain following single-visit root canal treatment: a triple-blind randomized clinical trial. Int Endodontic J 2017 Jan 30. doi: 10.1111/iej.12749.

Q Would it be true to say that?
A Patients who had the 2.5% NaOCl option took fewer analgesics
B Patients in both 2.5% or 5.25% NaOCl groups took the same number of analgesics
C More pain was experienced by patients in the 2.5% NaOCl cohort
D Less pain was experienced by patients in the 2.5% NaOCl cohort

8.Topical solution

These authors investigated the effects of topical anaesthesia on needle insertion and injection pain in the labial mucosa of maxillary central incisors of 44 patients awaiting apical surgery and to assess the relationship between patients’ anxiety and pain scores. All patients completed the Modified Dental Anxiety Scale questionnaire. One piece of xylocaine gauze was applied to the right or left side of the labial vestibule below the central incisor according to a randomisation process, and one piece of water gauze was applied to the contralateral side of the labial vestibule. Each piece of gauze remained in place for two minutes. The subjects were asked to rate their pain immediately after needle insertion and anaesthetic solution injection. The topical anaesthetic was highly effective for both insertion and injection pain during infiltration anaesthesia for the maxillary central incisors. Highly anxious patients reported higher pain scores; however, topical anaesthetics reduced the effect of anxiety on increasing pain.

Cho SY et al. Effect of topical anesthesia on pain from needle insertion and injection and its relationship with anxiety in patients awaiting apical surgery: a randomized double-blind clinical trial. J Endodontics 2017 43: 364-369.

Q In this study:
A Highly anxious patients perceived no benefit from topical anaesthesia
B All patients reported effective pain relief from topical anaesthesia
C Topical anaesthesia improved pain on needle insertion but not on injection
D Moderately anxious patients reported less benefit than highly anxious patients