Flare-ups in endodontics: II. Therapeutic measures

Factors that affect the outcomes of root canal treatment and retreatment-A reframing of the principles

This paper undertakes a broad and comprehensive synthesis of relevant clinical, biological, biomechanical, technical and healthcare services data to understand the factors affecting outcomes of periapical healing after root canal (re)treatment. The medical and dental evidence-based era (1980-present) is contextualized with the earlier evidence drive in endodontics (1911-1940) triggered by the focal infection era. The current evidence-based approach has a sharper focus on evidence quality and derivation of practice guidelines. Contrary views question whether guideline-driven, or expertise-development-driven endeavours would best serve outcome improvement in society. The endodontic discipline functions in a broad healthcare framework and sustains industrial, economic and trend pressures that may be deemed to influence outcomes. The nature of root canal treatment and the challenges in determining the factors that affect its outcomes is discussed. The factors potentially affecting periapical healing after root canal treatment are classified into pre-operative, intra-operative and postoperative groups. These categories subsume multiple elements with interactive influences, creating a complex picture, further confounded by some apparently surprising, counter-intuitive and contradictory findings. The technical versus biological conundrum in root canal treatment continues to cause cognitive dissonance. However, due reflection and cross-discipline-synthesis resolve the apparent data conflicts into a very simple, consistent and plausible picture of how root canal treatment works and the key factors that affect periapical healing. Root canal retreatment is considered mainly in the context of its differences from primary treatment as the majority of factors influencing outcomes are common to both. The exceptional difference is that retreatments have a proportionately reduced probability of healing by virtue of compromised apical root canal ramification access or modified host/infection interactions. Root canal (re)treatment outcomes are dominantly influenced by the nature of prior dynamic host/infection interaction (pre-operative patient factors) and how the direction of this dynamic is influenced by two factors: (1) the active efficacy of the operators' root canal treatment protocol to sustain a microbial ecological shift (intra-operative treatment factors) and dampen periapical inflammation; and (2) the passive ability of the functional tooth (and its restoration margin) to maintain its integrity to resist infection reversal (postoperative restorative factors).

The effect of antibiotic use on endodontic post-operative pain and flare-up rate: a systematic review with meta-analysis

Aim Antibiotics are widely used to prevent flare-ups after endodontic treatment of non-vital teeth. This systematic review assessed the effect of antibiotic administration on post-endodontic treatment pain and flare-up rate.Methods Five major databases including Web of Science, Cochrane Library, PubMed, Scopus and Embase were searched to identify randomised clinical trials (RCTs) published until September 2020. Retrieved papers were critically appraised using the revised Cochrane risk of bias tool (RoB 2). To reduce the clinical heterogeneity, the included studies were divided into two groups: studies on symptomatic non-vital teeth and studies on asymptomatic non-vital teeth. The primary outcomes were 'post-operative pain' and 'flare-up rate'. The data of included studies were statistically combined through meta-analysis using random-effect model. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence.Results Six RCTs involving two RCTs (N = 61) on symptomatic teeth and four RCTs (N = 310) on asymptomatic teeth were included. In two RCTs on asymptomatic teeth, prophylactic antibiotic had been used, while in the remaining two RCTs, antibiotics had been administered after treatment. Quantitative synthesis of the RCTs showed that antibiotic administration following endodontic treatment of symptomatic non-vital teeth has no effect on pain severity at 24 hours following treatment (weighted mean difference [WMD] = -0.03; 95% confidence interval [CI]: -0.53 to 0.47), and the use of antibiotics before endodontic treatment of asymptomatic non-vital teeth has no effect on flare-up rate (relative risk [RR] = 0.58; 95% CI: 0.22-1.54). The GRADE approach revealed that the overall quality of evidence on the topic is low.Conclusions The antibiotic administration following endodontic treatment of symptomatic non-vital teeth has no effect on pain severity at 24 hours following treatment. Also, prophylactic antibiotics are ineffective in reducing the flare-up rate following treatment of asymptomatic non-vital teeth. However, to evaluate the effect of post-treatment antibiotics on flare-up rate in asymptomatic non-vital teeth, more high-quality RCTs are needed.

Postoperative pain after different irrigation activation techniques: a randomized, clinical trial

The aim of this study was to assess the effectiveness of irrigation activation techniques on postoperative pain (PP) in mandibular premolar teeth with irreversible pulpitis after single-visit endodontic treatment. A total of 160 patients with symptomatic irreversible pulpitis were included in this prospective randomized clinical study. Four different activation methods were used in mandibular premolar teeth. In group 1, teeth were irrigated with side-port endodontic needles (NI) without any agitation; in groups 2 and 3, sonic activation was performed using EDDY and EndoActivator (EA), respectively; and in group 4, passive ultrasonic irrigation (PUI) was used. Patients' analgesic intake-as well as pain intensity during and after treatment-were recorded at 8, 24, 48 h and 7 days. The data relating to age, sex and analgesic intake was evaluated using the Chi-square test and the preoperative pain and PP intensity at different time intervals was evaluated with the Kruskal-Wallis test at a 5% significance level. Highest PP was recorded at 8 h, pain intensity decreased in all groups by the time. Pain in the NI group was found higher than that of EDDY group at 24 h (P < 0.05). EA and PUI had caused mild pain and had similar pain scores at 24 h. (P > 0.05). No statistically difference was found among the groups with regard to analgesic intake (P > 0.05). Although there were slight differences in PP levels between the groups at 24 h, pain levels decreased in all groups after 24 h. Activation of the irrigation solution did not make any difference in terms of PP after 24 h.

Triple antibiotic paste: momentous roles and applications in endodontics: a review

This study investigated the latest findings and notions regarding ‘triple antibiotic paste’ (TAP) and its applications in dentistry, particularly endodontics. TAP is a combination of 3 antibiotics, ciprofloxacin, metronidazole, and minocycline. Despite the problems and pitfalls research pertaining to this paste has unveiled, it has been vastly used in endodontic treatments. The paste's applications vary, from vital pulp therapy to the recently introduced regeneration and revascularisation protocol. Studies have shown that the paste can eliminate the root canal microorganisms and prepare an appropriate matrix for further treatments. This combination is able to remove diverse groups of obligate and facultative gram-positive and gram-negative bacteria, providing an environment for healing. In regeneration protocol cases, this allows the development, disinfection, and possible sterilization of the root canal system, so that new tissue can infiltrate and grow into the radicular area. Moreover, TAP is capable of creating a discipline in which other wanted and needed treatments can be successfully performed. In conclusion, TAP, as an antibacterial intracanal medication, has diverse uses. Nevertheless, despite its positive effects, the paste has shown drawbacks. Further research concerning the combined paste and other intracanal medications to control microbiota is a must.

Comparison of apical extrusion of intracanal bacteria by various glide-path establishing systems: an in vitro study

OBJECTIVES

This study compared the amount of apically extruded bacteria during the glide-path preparation by using multi-file and single-file glide-path establishing nickel-titanium (NiTi) rotary systems.

MATERIALS AND METHODS

Sixty mandibular first molar teeth were used to prepare the test apparatus. They were decoronated, blocked into glass vials, sterilized in ethylene oxide gas, infected with a pure culture of Enterococcus faecalis, randomly assigned to 5 experimental groups, and then prepared using manual stainless-steel files (group KF) and glide-path establishing NiTi rotary files (group PF with PathFiles, group GF with G-Files, group PG with ProGlider, and group OG with One G). At the end of canal preparation, 0.01 mL NaCl solution was taken from the experimental vials. The suspension was plated on brain heart infusion agar and colonies of bacteria were counted, and the results were given as number of colony-forming units (CFU).

RESULTS

The manual instrumentation technique tested in group KF extruded the highest number of bacteria compared to the other 4 groups (p < 0.05). The 4 groups using rotary glide-path establishing instruments extruded similar amounts of bacteria.

CONCLUSIONS

All glide-path establishment instrument systems tested caused a measurable apical extrusion of bacteria. The manual glide-path preparation showed the highest number of bacteria extruded compared to the other NiTi glide-path establishing instruments.

Debris extrusion by glide-path establishing endodontic instruments with different geometries

BACKGROUND/PURPOSE

Glide-path preparation is an important step during initial endodontic procedure to reduce shaping-instrument fracture. The aim of this study was to evaluate the amount of apically extruded debris produced by glide-path preparation instruments with different geometric designs.

MATERIALS AND METHODS

Forty teeth extracted for periodontal reasons were randomly divided into four groups (n = 10). The working length was standardized at 17 mm from the apical foramen by a flattening reference point. The glide-path was created using repetitive up-and-down movement three times with one of following four selected instruments: One G, ProGlider, a size 15 ScoutRace, and a size 15 stainless-steel K-file. To collect the apically extruded debris, the customized apparatus was used, and the collected debris was stored in an incubator. The weight of the debris was measured using an analytical balance with an accuracy of 0.00001 g. The data were analyzed by one-way analysis of variance and Duncan's multiple comparison test at a significance level of 95%.

RESULTS

The ProGlider group produced significantly less debris extrusion relative to the other groups (P < 0.05). The One G and ScoutRace groups showed no significant difference, but debris production was lower than that observed for the stainless-steel group (P < 0.05).

CONCLUSION

Creating the glide-path using nickel-titanium rotary files produced lower amounts of debris extrusion than using manual stainless-steel files. The progressive taper design of ProGlider, the center-off cross-section of One G, and the alternative-pitch design of ScoutRace may have increased the efficiencies of debris removal with minimal extrusion during glide-path preparation. Glide-path preparation using NiTi rotary files have better clinical efficiency than the manual stainless-steel file.

Comparison of apically extruded debris after large apical preparations by full-sequence rotary and single-file reciprocating systems

AIM

To evaluate the amount of apically extruded debris produced by ProTaper Universal (PTU), ProTaper Next (PTN), WaveOne (WO) and Reciproc (R) systems after large apical preparations.

METHODOLOGY

Sixty mandibular premolars with a single canal were selected and randomly assigned into 4 groups (n = 15) according to the system used for root canal preparation: PTU, PTN, WO and R groups. Canal preparations were performed up to size 40 in each group. Distilled water was used as an irrigant, and the apically extruded debris from each tooth was collected in pre-weighted glass vials and dried. The average weight of debris was assessed using a microbalance, and the data were analysed statistically using one-way analysis of variance and the post hoc Tukey multiple comparison test (α = 0.05).

RESULTS

The PTU system was associated with significantly more debris than the other systems (P < 0.05). No significant differences were found between PTN, WO and R systems (P > 0.05).

CONCLUSIONS

All systems were associated with apical debris extrusion when canals were prepared to a large apical size. The PTU system was associated with more debris extrusion.

Biologic perspectives to support clinical choices in root canal treatment

Some of the most keenly debated issues in endodontics have revolved around the where to end the root filling, as well as cleaning and shaping and obturation techniques. In some respects, original scientifically-based concepts have been abandoned in favour of clinical techniques that may provide aesthetically pleasing radiographs, but do not necessarily support tissue regeneration around the root apex following obturation. Recently advocated obturation techniques supporting the use of resin-based and bonded materials have not had the same extensive evaluation that gutta-percha, when in contact with the periradicular tissues, has had. Further studies are necessary so that evidence-based data can support the confident use of these innovative materials.

Prevalence of and factors affecting postpreparation pain in patients undergoing two-visit root canal treatment

AIM

This longitudinal, prospective study (i) investigated the prevalence of postpreparation pain during root canal treatment and (ii) evaluated the influence of factors affecting the pain experience.

METHODOLOGY

Twenty practitioners, comprising general dental practitioners, MSc graduates and endodontists, participated in this study. The patient sample (n=272) was derived from consecutive patients attending the practitioners' surgeries for a two-visit root canal treatment on a single tooth. Demographic, medical history, preoperative and intraoperative data as well as pain experience on days 1 and 2 after root canal preparation were recorded. Intensity of pain experienced was recorded on a visual analogue scale (VAS) of 0-5. The data were analysed using logistic regression models.

RESULTS

The prevalence of postpreparation pain within 48 h after treatment was 64.7% (n=176), but less than 10% of patients experienced severe pain (VAS 4 or 5) on either day 1 or day 2. The presence of preoperative pain (OR=2.841, P<0.001), tooth type (OR=2.008, P=0.009), systemic steroid therapy for other medical reasons (OR=0.181, P=0.023) and preoperative swelling (OR=2.433, P=0.040) were the only factors to significantly influence postpreparation pain experience.

CONCLUSIONS

The prevalence of postpreparation pain was high, and the important prognostic determinants were presence of preoperative pain, tooth type, systemic steroid therapy and preoperative swelling.

The location of the cementodentinal junction in single-rooted mandibular first premolars from Egyptian and Saudi patients: a histological study

AIM

To determine the location of the cementodentinal junction (CDJ) in mandibular first premolars from Egyptian and Saudi patients.

METHODOLOGY

One hundred and twenty-two extracted single-rooted mandibular first premolars (68 Egyptian; 54 Saudi) were examined histologically. Half of the teeth were fixed, decalcified, embedded in paraffin, mesio-distally sectioned and stained with H&E, whilst the other half were ground with a stone prior to microscopic evaluation. Measurements of the location of the CDJ were made parallel to the long axis of the teeth from the external surface of the root apex on the mesial and distal sides of the canal. Measurements were statistically analysed using two-way anova of repeated-measure design.

RESULTS

The CDJ in Egyptian sections ranged from 0 to 2.0 mm (mean +/- SD = 0.9 +/- 0.4 mm) on the mesial side of the canal and from 0.2 to 2.5 mm (mean +/- SD = 1.0 +/- 0.5 mm) on the distal aspect. In the Saudi sample, the CDJ ranged from 0.5 to 1.2 mm (mean +/- SD = 0.8 +/- 0.3 mm) on the mesial side and from 0.6 to 0.9 mm (mean +/- SD = 0.7 +/- 0.4 mm) on the distal side. The mesial and distal differences between Egyptian and Saudi premolars on the mesial and distal surface were statistically significant (P < 0.001).

CONCLUSIONS

The location of the CDJ varied between the Egyptian and Saudi mandibular first premolars, indicating that this junction is not a fixed point in populations of different countries.

Delayed root canal therapy: an analysis of treatment over time

A retrospective study of 898 teeth receiving root canal therapy was performed to document the sequelae of delayed completion of root canal treatment. Teeth were categorized into a prompt treatment group and a delayed treatment group. Comparisons of prompt and delayed treatment groups were made with regard to preoperative pain, interappointment emergencies, postobturation pain, and final treatment. Findings from this study show that a palliative endodontic procedure is an extremely effective treatment. However, 56% of teeth with incomplete root canal therapy eventually were extracted compared with 2 to 3% for the root canal filling treatment groups. By emphasizing the potential loss of the tooth rather than the potential of interappointment emergencies, the clinician may be more effective in achieving compliance among patients receiving delayed treatment.

Report of Committee on Scientific Investigation of the American Academy of Restorative Dentistry

A few personal points seem appropriate in summary. It is axiomatic that while research solves problems, it also creates them. As an example, it is an accepted fact that dentistry more than any other profession has made serious inroads into putting itself out of business through research. Each year this report takes note of the reduction in dental caries in children, which has thus triggered a change in the nature of general practice. Be this as it may, it is well to acknowledge that major dental diseases are not disappearing, but their patterns in the population are changing, accompanied by an expansion of other services. Despite the optimistic picture painted earlier in this report, it is grossly premature to acclaim the elimination of caries, and thereby a significant segment of restorative dentistry. Of course the younger age groups have been the major beneficiaries of caries reduction. As the child ages from 9 to 16 years, the percentage of mouths free of caries drops by one half. In addition, the disease pattern in the adult population is being altered because of a longer life span and loss of fewer teeth. Unquestionably what we will, and are already seeing, is not an elimination of restorative dentistry but a different target and changes in procedures because of new materials, therapy, and expanded scope of services. There is yet another subtle change in the trend of dental research and it deals with the reduction in the number of dental schools worldwide and smaller class sizes in those schools. Dental research thereby suffers because of the traditional link between education and research. Thus the potential pool of researchers becomes smaller and research monies for training programs for dental investigators, particularly in clinical research, decreases. This year a surprising number of articles are concerned with manpower as it relates to research priorities. So, it is indeed a time that both the profession and the scientific community find filled with controversy and frustration. Yet never has there been a time that offers more in challenges and rewards.