Abstract
Objective
This study aims at comparing treatment outcome and tooth survival of root canal–filled teeth following manual vs rotary instrumentation techniques over a 5-year period.
Methods
This was a single-centre study conducted as a follow-up to a short-term parallel-arm randomised controlled noninferiority trial in which root canal treatment was performed on teeth using either rotary or manual instrumentation. Patients were monitored at post 6-month, 1-year, 4-year, and 5-year review periods by blinded evaluators. Treatment outcome was categorised as favourable, uncertain, and unfavourable (employing European Society of Endodontology categorisation based on strict clinical and radiographic criteria), and 5-year tooth survival was determined by assessing whether tooth was in situ in the oral cavity or extracted. The Kaplan–Meier method and log rank test evaluated tooth survival. P value <.05 was considered statistically significant.
Results
Ninety of 120 treated teeth were assessed in 37 men and 40 women with mean age of 30.6 ± 10.99 years. Treatment outcome was significantly more favourable in the rotary group compared to the manual group at post 6-month (P = .021) and 1-year (P = .043) review periods. The differences in favourable outcome (P = .498) and tooth survival (P = .296) between the 2 groups were, however, not significant at the 5-year review period.
Conclusions
The rotary instrumentation technique was shown to be more effective in resolving clinical symptoms and promoting periapical healing after the post 6-month and 1-year review compared to the manual instrumentation technique; however, both groups had similar favourable outcomes and survival rates after an extended 5-year review period.
Key words: Manual instrumentation, Root canal treatment, Rotary instrumentation, Tooth survival, Treatment outcome
Introduction
The aim of root canal treatment (RCT) is to eliminate inflamed and infected pulpal tissue, thus providing an environment that promotes healing, and arrests the progression of periapical pathology. Periapical healing encourages the long-term retention of functional, endodontically treated teeth.1, 2, 3, 4
Outcomes of RCT are of significant interest in endodontics. Dental clinicians must possess the right skill and judgement during endodontic outcome assessment to determine whether RCT is successful. Endodontic success is determined after a root-filled tooth has been subjected to different functional activities over time. Evaluating such success requires the adoption of specific criteria. Notably, overlapping criteria have been employed in different studies.1,2,5, 6, 7, 8 The inconsistency in endodontic success classification, varying from consideration of a symptomless and clinically functional tooth to strict radiographic healing, has led to misdiagnosis and unnecessary re-treatment. The differences in success rates reported in the literature have been attributed to varying durations of postoperative review, criteria used to categorise outcome, radiographic evaluation, and clinical experience.2
The European Society of Endodontology (ESE) has set out guidelines using both clinical and radiographic parameters to categorise treatment outcomes as “favourable,” “uncertain,” and “unfavourable” after a minimum of 4 years’ monitoring.5 It has been recommended that endodontic success should be evaluated based on the assessment of the dentist (objective) and the patient (subjective). The dentist's assessment involves both clinical and radiographic review. The patient's assessment centres on tooth survival, which focusses on the tooth being asymptomatic and functional in the dentition, which—though it is an insufficient biological goal of treatment—is satisfactory for the patient.4 Tooth survival as a measure of endodontic success refers to the tooth being present in the oral cavity 12 months or more after initial RCT, whereas a failure is recorded if the tooth is extracted at any time following treatment.2,3,4,8, 9, 10 The long-term survival following RCT is of high priority and focus in modern tooth conservation.11
Few retrospective studies have evaluated the impact of recent advancements in canal preparation techniques on endodontic success.2,12,13 Therefore, to ascertain endodontic success in relation to preparation techniques, there is the need for extended patient follow-up for continued assessment of root-filled teeth for a minimum of 4 years according to ESE recommendations.5 This study was thus conducted to determine endodontic success at 5 years post-RCT; short-term results were previously published.14 Two measures—treatment outcome as categorised by the ESE5 and tooth survival over a 5-year review period—were employed in the evaluation sequel to use of either manual or rotary instrumentation techniques during RCT.
Material and methods
This present study is a follow-up to a previous randomised controlled noninferiority trial (2 parallel-group design)14 conducted at the Restorative Dental Clinics, Lagos University Teaching Hospital, Nigeria, after obtaining institutional ethical approval with assigned numbers for the trial and follow-up study (ADM/DCST/HREC/1684 and ADM/DCST/HREC/APP/3096, respectively, accessed at Pan African Clinical Registry with registration number PACTR201804003323280). This follow-up study follows Consolidated Standards of Reporting Trials (CONSORT) guidelines. The CONSORT flow diagram and checklist are provided as supplementary materials.
Eligibility criteria of prior clinical trial
Participants recruited were consecutive adult patients who presented between April 2014 and March 2015, met the inclusion criteria15 for single-visit RCT, and signed a written consent. Inclusion criteria were anterior, premolar, or first molar teeth (maxillary or mandibular) with no pain or mild to moderate preoperative pain; diagnosed with irreversible pulpitis, nonvital with no periapical involvement, uncomplicated coronal fracture, or apical periodontitis not exceeding 2 × 2 mm periapical radiolucency. Teeth with severe pain; weeping canals, or periapical abscess; periodontally compromised teeth; teeth with calcified canals, external and internal root resorption; excessively curved roots; unrestorable teeth; cases of RCT retreatment; as well as uncooperative and medically compromised patients (ASA Physical Status Classification III and beyond)16 were excluded from the study.
Sample size determination and randomisation
This study was a follow-up of a previous study14 and followed on the calculated sample size of 28 teeth per group using the formula for comparing 2 independent proportions by Varkevisser et al17 based on a previous study by Wei et al.18 Alpha-error was set at 0.05 and power was set at 80%. Considering that single- and multi-rooted teeth were included and to compensate for attrition, the required sample size per group was increased to 60.
The randomisation process was performed by 2 endodontists in training. After each participant met the inclusion criteria, the tooth was randomly assigned into either of the 2 groups (by picking out of 120 concealed envelopes, each containing a tagged slip). Patients who required RCT for multiple teeth but not more than 2 teeth, one each on the left and right sides, had them randomly assigned to ensure objectivity and to maintain an equal sample size.
Intervention and postoperative assessment of the prior clinical trial
Comprehensive history and examination, electric pulp tests, tooth percussion, and radiographic investigations were performed to arrive at a diagnosis. Canal preparation was performed after access cavity preparation and working length determination using either manual step-back technique with stainless steel K-files (size 06-80; Mani, Inc) or ProTaper Universal rotary files (Shaping files Sx, S1, and S2 and finishing files F1, F2, and/or F3; Dentsply Maillefer Ballaigues) by continuous rotary instrumentation in a crown-down manner using an X-Smart Plus endomotor (Dentsply Maillefer). The same amount of irrigating solution, 2.5% sodium hypochlorite (Reckitt Benckiser) at 30 mL per canal, was used in each group, and RC Prep (Stone Pharmaceuticals) was used for canal lubrication. A 30-G needle with a rubber stopper length-guide was advanced into the canal as far as 2 mm short of the working length and was moved up and down during irrigation. Approximately 3 mL of 17% EDTA (Prevest DenPro Ltd.) was used post–canal preparation to remove the smear layer. A post-obturation radiograph was taken immediately and obturation repeated in the event of apical extrusion of gutta percha (GP), when GP did not fill the entire canal length, or in cases of existing voids within the filling. All treatments were performed by a single operator to eliminate interoperator bias, and all procedures were performed in accordance with ethical standards set forth in the Declaration of Helsinki (as revised in Brazil 2013).
Treatment outcome assessment for the present follow-up study
Assessments were carried out by 2 independent evaluators (endodontists) who were blinded to the groupings. Precalibration of evaluators yielded good intra- and interexaminer agreements, as shown by Cohen's kappa values, which ranged from 0.88 to 0.94 for all measured criteria.
Treatment outcome was based on the guidelines set by ESE5 and tooth survival.2 Pain rating was obtained after employing the Universal Pain Assessment Tool (Wong-Baker FACES Pain Rating Scale).19 Tooth mobility was elicited and graded according to Miller's index.20 For radiographic assessment, periapical radiograph was used as recommended for routine endodontic evaluation.21 A modified periapical index (PAI) scoring system was used to assess for periapical lesions.2 Teeth were classified as having a periapical lesion when the PAI score was 3 or greater.2 The size of any radiolucency was determined by measuring the largest horizontal and vertical width with a ruler in millimetres.22 Preoperative radiographic findings were compared with radiographic findings from the post 6-month, 1-year, 4-year, and 5-year follow-up periods to determine whether radiolucency was a new postoperative lesion or a preexisting lesion that had remained the same size, decreased, or increased. Multi-rooted teeth were assigned the highest PAI score of their roots.23 Where there was contradiction between evaluators, the radiograph was discussed until a consensus was reached or the higher score was adopted. Teeth with absence of any sign or symptoms regardless of PAI score were considered functional and thus regarded as a success.2,6
Tooth survival was referred to as evidence of a tooth being present 12 months or more after RCT. A tooth was classified a failure if extracted at any time after treatment.2 Treatment outcome was classified as “favourable,” according to the ESE, when the tooth was asymptomatic and had radiologic evidence of a normal periodontal ligament space.5 An “uncertain” outcome was defined as presence of radiographic evidence revealing a periapical lesion that has remained the same size or has only decreased in size within 4 years of monitoring.5 The outcome was considered “unfavourable” when the tooth was symptomatic, if there were signs of continuing root resorption, if a subsequent radiographic lesion was detected, or when a prior periapical lesion increased in size or failed to resolve after 4-year monitoring.5
Statistical analyses
Statistical analyses were performed using IBM SPSS, version 23.0 (IBM Corporation). Descriptive analysis was carried out using frequency and proportion for categorical variables and mean and standard deviation for numeric variables. Data were statistically analysed using Pearson chi-square, Fisher exact test, and 2-sided linear-by-linear association, where applicable. Pearson correlation coefficient was employed to determine the level of correlation between preparation technique and postoperative clinical and radiographic findings, and treatment outcome. In terms of correlation coefficient, r ≤ 0.2 was considered as weak, >0.2–0.5 as moderate, >0.5–0.7 as strong, and >0.7 as very strong. Kaplan–Meier survival analysis and log-rank test were performed to visualise and compare the tooth survival probabilities based on instrumentation technique. All statistical tests were interpreted at a 5% significance level.
Results
Characteristics of participants/treated teeth
Results presented in this study represent the analysis of 90 root-treated teeth of 77 patients who were followed up from the previously reported trial.14 Eighteen patients with 30 teeth declined to continue participation after the 6-month review. Hence, a total dropout of 30 teeth (13 and 17 in the rotary and manual groups, respectively) was recorded after the 6-month review and no other dropout occurred during the continued 5-year review. Reasons for the dropouts in both groups were related to geographic relocation of some participants, whilst others declined to continue participation. Preoperative clinical and radiographic parameters of the 2 groups were not significantly different, as reported in the primary clinical trial.14 The sample comprised 37 men with 43 treated teeth and 40 women with 47 treated teeth; ages were between 18 and 62 years, with a mean age of 30.6 ± 10.99 years. The recruitment period was from April 2014 to March 2015, and the last recruit completed the 5-year follow-up in March 2020.
The post 6-month review was done at the seventh month after treatment for all teeth included in the follow-up study. The results of clinical, radiographic, and treatment outcomes, including tooth survival, are presented.
Clinical outcome
Fifty-eight (64.4%) of 90 teeth had mild or moderate pain prior to treatment. There was no pain incidence after the 6-month review; however, pain was recorded in one tooth in each group by the 4-year review period. Eleven teeth presented with grade I mobility pretreatment, and after treatment, grade I mobility was observed in a single tooth (manual group) at all review periods except at final review. Fifty percent of 90 teeth presented with preoperative tenderness to percussion, which totally resolved by the 6-month review. There was reccurrence in 2 teeth and 1 tooth at the 4-year review and the final review, respectively (Table 1). No other symptoms were recorded.
Table 1.
Relationship amongst pain, mobility, TTP, PR, and root canal preparation technique.
| Characteristic of pain | Preoperative pain (%) |
Post 6-month (7-month review) postoperative pain (%) |
1-year postoperative pain (%) |
4-year postoperative pain (%) |
5-year postoperative pain (%) |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| Rotary | Manual | Rotary | Manual | Rotary | Manual | Rotary | Manual | Rotary | Manual | |
| No pain | 14 (29.8) | 18 (41.9) | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 46 (97.9) | 42 (97.7) | 47 (100) | 42 (100) |
| Mild pain | 22 (46.8) | 16 (37.2) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 1 (2.1) | 1 (2.3) | 0 (0) | 0 (0) |
| Moderate pain | 11 (23.4) | 9 (20.9) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) |
| Total | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 47 (100) | 42 (100) |
| P value | .479 | N/A | N/A | .730 | N/A | |||||
| Characteristic of mobility | Preoperative mobility (%) |
Post 6-month postoperative mobility (%) |
1-year postoperative mobility (%) |
4-year postoperative mobility (%) |
5-year postoperative mobility (%) |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| Rotary | Manual | Rotary | Manual | Rotary | Manual | Rotary | Manual | Rotary | Manual | |
| No mobility | 45 (95.7) | 34 (79.1) | 47 (100) | 42 (97.7) | 47 (100) | 42 (97.7) | 47 (100) | 42 (97.7) | 47 (100) | 42 (100) |
| Grade 1 | 2 (4.3) | 9 (20.9) | 0 (0) | 1 (2.3) | 0 (0) | 1 (2.3) | 0 (0) | 1 (2.3) | 0 (0) | 0 (0) |
| Total | 47 (100) | 43 (100) | 47 (100) | 42 (100) | 47 (100) | 42 (100) | 47 (100) | 42 (100) | 47 (100) | 42 (100) |
| P value | .005* | .478 | .478 | .478 | N/A | |||||
| Characteristic of TTP | Preoperative TTP (%) |
Post 6-month postoperative TTP (%) |
1-year postoperative TTP (%) |
4-year postoperative TTP (%) |
5-year postoperative TTP (%) |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| Rotary | Manual | Rotary | Manual | Rotary | Manual | Rotary | Manual | Rotary | Manual | |
| Absent | 24 (51.1) | 21 (48.8) | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 46 (97.9) | 42 (97.7) | 47 (100) | 41 (97.6) |
| Present | 23 (48.9) | 22 (51.2) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 1 (2.1) | 1 (2.3) | 0 (0) | 1 (2.4) |
| Total | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 47 (100) | 42 (100) |
| P value | .500 | N/A | N/A | .730 | .472 | |||||
| Characteristic of PR | Preoperative PR (%) |
Post 6-month postoperative PR (%) |
1-year postoperative PR (%) |
4-year postoperative PR (%) |
5-year postoperative PR (%) |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| Rotary | Manual | Rotary | Manual | Rotary | Manual | Rotary | Manual | Rotary | Manual | |
| Absent | 37 (78.7) | 29 (67.4) | 46 (97.9) | 36 (83.7) | 46 (97.9) | 37 (86.0) | 46 (97.9) | 40 (93.0) | 46 (97.9) | 40 (95.2) |
| Same size | 0 (0) | 0 (0) | 0 (0) | 2 (4.7) | 1 (2.1) | 3 (7.0) | 1 (2.1) | 2 (4.7) | 1 (2.1) | 2 (4.8) |
| Increased | 10 (21.3) | 14 (32.6) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 1 (2.3) | 0 (0) | 0 (0) |
| Decreased | 0 (0) | 0 (0) | 1 (2.1) | 5 (11.6) | 0 (0) | 3 (7.0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) |
| Total | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 47 (100) | 42 (100) |
| P value | .149 | .038* | .033* | .216 | .457 | |||||
No teeth presented with severe pain; no grade 2 or 3 mobility. One tooth in the manual group was extracted due to vertical root fracture before the final review.
Statistical significance.
N/A represents no statistics for variables with all entries in only one group.
TTP, tooth tender to percussion; PR, periapical radiolucency.
Radiographic outcome
Fourteen (32.6%) and 10 (21.3%) teeth in the manual group and the rotary group, respectively, had preoperative periapical radiolucency. A significantly greater number of teeth in the manual group compared to the rotary group still had radiolucency at the post 6-month (P = .038) and 1-year (P = .033) follow-up. Moderate and significant correlations were seen between preparation technique and radiolucency measured at post 6-month (r = 0.219; P = .038) and 1-year (r = 0.226; P = .032) reviews. Radiolucency gradually resolved over the 5-year period except for 3 teeth in total that persistently presented with same-sized radiolucency.
Treatment outcome
Complicated coronal fracture and irreversible pulpitis recorded the most favourable outcomes throughout the different review periods (P < .05; Table 2). Overall, a more favourable outcome was noted when rotary instrumentation was used compared to manual instrumentation. This difference was statistically significant at the post 6-month and 1-year reviews (P = .021 and .043, respectively; Table 3). Moderate and significant correlations existed between preparation technique and treatment outcome at post 6-month (r = 0.248; P = .018) and 1-year (r = 0.221; P = .037) reviews. Teeth with a favourable outcome were similar in both groups by the final review (Table 3).
Table 2.
Relationship amongst gender, diagnosis, tooth location, tooth type, and treatment outcome in all treated teeth.
| Gender | Post 6-month (7-month review) treatment outcome (%) |
1-year treatment outcome (%) |
4-year treatment outcome (%) |
5-year treatment outcome (%) |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Favourable | Uncertain | Unfavourable | Favourable | Uncertain | Unfavourable | Favourable | Uncertain | Unfavourable | Favourable | Unfavourable | |
| Female | 44 (53.7) | 3 (37.5) | 0 (0) | 44 (53.0) | 3 (42.9) | 0 (0) | 46 (54.1) | 1 (25.0) | 0 (0) | 46 (53.5) | 1 (33.3) |
| Male | 38 (46.3) | 5 (62.5) | 0 (0) | 39 (47.0) | 4 (57.1) | 0 (0) | 39 (45.9) | 3 (75.0) | 1 (100) | 40 (46.5) | 2 (66.7) |
| Total | 82 (100) | 8 (100) | 0 (0) | 83 (100) | 7 (100) | 0 (0) | 85 (100) | 4 (100) | 1 (100) | 86 (100) | 3 (100) |
| P value | .308 | .450 | .301 | .790 | |||||||
| Diagnosis | Post 6-month treatment outcome (%) |
1-year treatment outcome (%) |
4-year treatment outcome (%) |
5-year treatment outcome (%) |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Favourable | Uncertain | Unfavourable | Favourable | Uncertain | Unfavourable | Favourable | Uncertain | Unfavourable | Favourable | Unfavourable | |
| Apical periodontitis | 45 (54.9) | 7 (87.5) | 0 (0) | 46 (55.4) | 6 (85.7) | 0 (0) | 48 (56.5) | 3 (75.0) | 1 (100.0) | 49 (57.0) | 2 (66.7) |
| Uncomplicated coronal fracture | 6 (7.3) | 0 (0) | 0 (0) | 6 (7.2) | 0 (0) | 0 (0) | 6 (7.1) | 0 (0) | 0 (0) | 6 (7.0) | 0 (0) |
| Irreversible pulpitis | 21 (25.6) | 0 (0) | 0 (0) | 21 (25.3) | 0 (0) | 0 (0) | 21 (24.7) | 0 (0) | 0 (0) | 21 (24.4) | 0 (0) |
| Pulp necrosis | 10 (12.2) | 1 (12.5) | 0 (0) | 10 (12.0) | 1 (14.3) | 0 (0) | 10 (11.8) | 1 (25.0) | 0 (0) | 10 (11.6) | 1 (33.3) |
| Total | 82 (100) | 8 (100) | 0 (0) | 83 (100) | 7 (100) | 0 (0) | 85 (100) | 4 (100) | 1 (100) | 86 (100) | 3 (100) |
| P value | .000* | .001* | .018* | .718 | |||||||
| Tooth location | Post 6-month treatment outcome (%) |
1-year treatment outcome (%) |
4-year treatment outcome (%) |
5-year treatment outcome (%) |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Favourable | Uncertain | Unfavourable | Favourable | Uncertain | Unfavourable | Favourable | Uncertain | Unfavourable | Favourable | Unfavourable | |
| Maxillary | 56 (68.3) | 4 (50.0) | 0 (0) | 56 (67.5) | 4 (57.1) | 0 (0) | 56 (65.9) | 3 (75.0) | 1 (100) | 57 (66.3) | 2 (66.7) |
| Mandibular | 26 (31.7) | 4 (50.0) | 0 (0) | 27 (32.5) | 3 (42.9) | 0 (0) | 29 (34.1) | 1 (25.0) | 0 (0) | 29 (33.7) | 1 (33.3) |
| Total | 82 (100) | 8 (100) | 0 (0) | 83 (100) | 7 (100) | 0 (0) | 85 (100) | 4 (100) | 1 (100) | 86 (100) | 3 (100) |
| P value | .251 | .429 | .723 | 1.000 | |||||||
| Tooth type | Post 6-month treatment outcome (%) |
1-year treatment outcome (%) |
4-year treatment outcome (%) |
5-year treatment outcome (%) |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Favourable | Uncertain | Unfavourable | Favourable | Uncertain | Unfavourable | Favourable | Uncertain | Unfavourable | Favourable | Unfavourable | |
| Anterior | 36 (43.9) | 6 (75.0) | 0 (0) | 37 (44.6) | 5 (71.4) | 0 (0) | 39 (45.9) | 2 (50.0) | 1 (100) | 39 (45.3) | 2 (66.7) |
| Posterior | 46 (56.1) | 2 (25.0) | 0 (0) | 46 (55.4) | 2 (28.6) | 0 (0) | 46 (54.1) | 2 (50.0) | 0 (0) | 47 (54.7) | 1 (33.3) |
| Total | 82 (100) | 8 (100) | 0 (0) | 83 (100) | 7 (100) | 0 (0) | 85 (100) | 4 (100) | 1 (100) | 86 (100) | 3 (100) |
| P value | .449 | .568 | .892 | .767 | |||||||
One tooth was extracted due to vertical root fracture before the final review.
Statistical significance.
N/A represents no statistics for variables with all entries in only one group.
Table 3.
Relationship between treatment outcome and root canal preparation technique at different review periods.
| Treatment outcome | Post 6-month (7-month) treatment outcome (%) |
1-year treatment outcome (%) |
4-year treatment outcome (%) |
5-year treatment outcome (%) |
||||
|---|---|---|---|---|---|---|---|---|
| Rotary | Manual | Rotary | Manual | Rotary | Manual | Rotary | Manual | |
| Favourable | 46 (97.9) | 36 (83.7) | 46 (97.9) | 37 (86.0) | 45 (95.7) | 40 (93.0) | 46 (97.9) | 40 (95.2) |
| Uncertain | 1 (2.1) | 7 (16.3) | 1 (2.1) | 6 (14.0) | 2 (4.3) | 2 (4.7) | 0 (0) | 0 (0) |
| Unfavourable | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 1 (2.3) | 1 (2.1) | 2 (4.8) |
| Total | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 47 (100) | 43 (100) | 47 (100) | 42 (100) |
| P value | .021* | .043* | .572 | .498 | ||||
One tooth in the manual group was extracted due to vertical root fracture before the final review.
Statistical significance.
N/A represents no statistics for variables with all entries in only one group.
Survival analysis
The survival probability of the rotary group (100%) was greater than that of the manual group (97.7%) at the 5-year review; however, this finding was not statistically significant (P = .296). One tooth in the manual group was extracted due to a vertical root fracture (Figure 1).
Fig.
Kaplan–Meier survival curve.
Discussion
The ESE recommends that endodontic success or failure may be fully ascertained only after 4 years posttreatment.5 This supports the report of Molven et al24 that emphasised that even though RCT might appear successful shortly after treatment, a minimum of a 4-year review is of utmost importance to be conclusive. Therefore, this study adopted a long-term evaluation to determine endodontic success. Longevity is a key consideration in RCT, which is addressed by tooth survival.7 Tooth survival is a patient-centred measure of endodontic success, whereas treatment outcome—which considers periapical healing—is a clinician's more objective view of success.3, 4, 5
The rotary group had a significantly (P < .05) more favourable outcome compared to the manual group at the post 6-month and 1-year review periods. However, there was no significant difference (P > .05) in long-term outcomes in the 2 groups. Rotary and manual instrumentation both resulted in high and comparable favourable outcome and 5-year survival. This supports the minimum of 4-year recommendation to ascertain endodontic success.5,24 A retrospective study by Cheung and Liu12 reported similar findings of a significantly higher favourable outcome over a short-term review following rotary as compared to manual RCT. The higher outcome noted in the rotary group may be attributed to evidence of a lesser amount of debris extrusion periapically with subsequent faster periapical healing.25,26 Apical debris extrusion, which occurs more in hand instrumentation, may in turn lead to an inflow of blood and exudate which encourages further multiplication of intracanal bacteria, further worsening the chronic periapical lesion.25 The similar 5-year survival rate noted in the 2 groups in this study is consistent with that of a retrospective study by Fleming et al,2 who employed tooth survival as a success criterion in 2 technique groups after a long-term follow-up.
Complete pain resolution at the end of the preceding short-term clinical trial14 coincided with nil pain at the commencement of this study. However, 2 participants, one in each group, experienced mild pain at the 4-year review that totally resolved by the final review. The mild pain may be due to periodontal causes or occlusal trauma, which the patient could not recollect during the review and which are conditions unrelated to prior pulpal or periapical pathology.
Tooth tenderness totally resolved in both groups by the post 6-month review. However, tenderness was noted in 2 teeth, one in each group, when assessed at the 4-year review and in 2 teeth only in the manual group at the final review. These patients were noted to exhibit some plaque retention around the restoration margins and periodontal pockets measuring 4 to 5 mm in depth. It is therefore likely that tooth tenderness experienced by these patients was due to periodontal causes.
The significantly lower number of teeth with periapical radiolucency in the rotary group compared to the manual group at 6-month and 1-year review supports the report of better periapical healing following rotary instrumentation due to reduced incidence of pulpal debris extrusion.26,27 The increased debris extrusion containing micro-organisms associated with hand instrumentation would further aggravate the inflammation and slow the periapical healing rate.25 Because more than 40% of patients in each group presented with apical periodontitis prior to RCT,14 the significant difference in periapical healing in both groups during the intermediate reviews buttresses this explanation. Cheung and Liu also reported significantly better periapical healing following rotary instrumentation after short-term monitoring.12 Similar healing rates were, however, observed in both groups in our study after long-term monitoring.
The high rate of tooth retention and favourable outcomes following RCT performed by a skilled operator in this study support the view that endodontic success is highly dependent on the operator's expertise. This effect was demonstrated by Cheung and Liu,12 wherein RCT performed by postgraduate students had significantly higher success rates than those performed by undergraduates.
Limitations of this study are similar to most extended follow-up studies, and not all participants included in the previous clinical trial consented to participate in the follow-up study. Withdrawals from clinical trials normally occur, but the 25% dropout rate in this study (following the short-term study) may have caused the available data to be subject to potential bias and reduced the sensitivity of analysis. A larger sample size of the clinical trial, if available for this present study, would have given more representative results. However, it is worth noting that despite the dropouts, the total number of teeth reviewed in the present study was still greater than the minimum sample size, since we considered the possibility of attrition. Further extended studies are recommended for the review of the remaining patients who continued the present follow-up study.
Ideally, whenever possible, the basic unit of sample population in similar clinical studies is the patient rather than the tooth. It becomes difficult to adhere to this ideal in cases such as this study, in which some participants had a left and a right tooth that met the inclusion criteria and both teeth were inculded as their reponse to tratment in general reflected the overall expeimental conditions. Although this study has endeavoured to take the patient into account, it did not accurately reflect the clinical experience of the study population since the patient selection was not exclusively on a per-tooth basis.
The high 5-year success rate in both groups differs from the significantly better outcome observed in the rotary group during the short-term (post 6-month and 1-year) assessment period. Although this can be explained by the usual continuous resolution of postoperative pain, swelling, and periapical pathology that follows a successful RCT, a paucity of comparable data makes it difficult to draw a definitive conclusion. We therefore recommend that more long-term follow-up studies be performed to determine the difference in treatment outcomes following RCT performed using either manual or rotary instrumentation technique.
Conclusions
The rotary instrumentation technique was shown to be more efficacious in promoting postendodontic healing at the short-term review periods compared to the manual instrumentation technique after single-visit RCT; however, both groups had similar favourable outcomes and survival rates after an extended 5-year monitoring period.
Author contributions
John O. Makanjuola: conceptualisation, methodology, investigation, project administration, resources, formal analysis, visualisation, writing–original draft, and writing–review and editing.
Olabisi H. Oderinu: conceptualisation, methodology, supervision, validation, and writing–review and editing.
Donna C. Umesi: conceptualisation, methodology, supervision, validation, and writing–review and editing.
Conflict of interest
None disclosed.
Acknowledgments
Acknowledgements
The authors express their sincere gratitude to Drs Idon, Sotunde, Egbunah, Aladenika, and Adeoye for their contributions during the inputing of data, statistical analysis, and preparation of the manuscript.
Footnotes
Supplementary material associated with this article can be found in the online version at doi:10.1016/j.identj.2022.08.008.
Appendix. Supplementary materials
REFERENCES
- 1.Zahran S, Patel S, Koller G, Mannocci F. The impact of an enhanced infection control protocol on molar root canal treatment outcome–a randomized clinical trial. Int Endod J. 2021;54:1993–2005. doi: 10.1111/iej.13605. [DOI] [PubMed] [Google Scholar]
- 2.Fleming CH, Litaker MS, Alley LW, Eleazer PD. Comparison of classic endodontic techniques versus contemporary techniques on endodontic treatment success. J Endod. 2010;36:414–418. doi: 10.1016/j.joen.2009.11.013. [DOI] [PubMed] [Google Scholar]
- 3.Riis A, Taschieri S, Del Fabbro M, Kvist T. Tooth survival after surgical or nonsurgical endodontic retreatment: long-term follow-up of a randomized clinical trial. J Endod. 2018;44:1480–1486. doi: 10.1016/j.joen.2018.06.019. [DOI] [PubMed] [Google Scholar]
- 4.Kebke S, Fransson H, Brundin M, Mota de Almeida FJ. Tooth survival following root canal treatment by general dental practitioners in a Swedish county–a 10-year follow-up study of a historical cohort. Int Endod J. 2021;54:5–14. doi: 10.1111/iej.13392. [DOI] [PubMed] [Google Scholar]
- 5.European Society of Endodontology Quality guidelines for endodontic treatment: consensus report of the European Society of Endodontology. Int Endod J. 2006;39:921–930. doi: 10.1111/j.1365-2591.2006.01180.x. [DOI] [PubMed] [Google Scholar]
- 6.Azim AA, Griggs JA, Huang GJ. The Tennessee study: factors affecting treatment outcome and healing time following nonsurgical root canal treatment. Int Endod J. 2016;49:6–16. doi: 10.1111/iej.12429. [DOI] [PubMed] [Google Scholar]
- 7.Estrela C, Holland R, Estrela CR, et al. Characterization of successful root canal treatment. Braz Dent J. 2014;25:3–11. doi: 10.1590/0103-6440201302356. [DOI] [PubMed] [Google Scholar]
- 8.Chatzopoulos GS, Koidou VP, Lunos S, Wolff LF. Implant and root canal treatment: survival rates and factors associated with treatment outcome. J Dent. 2018;71:61–66. doi: 10.1016/j.jdent.2018.02.005. [DOI] [PubMed] [Google Scholar]
- 9.Vahdati SA, Torabinejad M, Handysides R, Lozada J. A retrospective comparison of outcome in patients who received both nonsurgical root canal treatment and single-tooth implants. J Endod. 2019;45:99–103. doi: 10.1016/j.joen.2018.10.018. [DOI] [PubMed] [Google Scholar]
- 10.Lane J, Bonsor S. Survival rates of teeth treated with bacterial photo-dynamic therapy during disinfection of the root canal system. Br Dent J. 2019;226:333–339. doi: 10.1038/s41415-019-0026-z. [DOI] [PubMed] [Google Scholar]
- 11.Borén DL, Jonasson P, Kvist T. Long-term survival of endodontically treated teeth at a public dental specialist clinic. J Endod. 2015;41:176–181. doi: 10.1016/j.joen.2014.10.002. [DOI] [PubMed] [Google Scholar]
- 12.Cheung GS, Liu CS. A retrospective study of endodontic treatment outcome between nickel-titanium rotary and stainless steel hand filing techniques. J Endod. 2009;35:938–943. doi: 10.1016/j.joen.2009.04.016. [DOI] [PubMed] [Google Scholar]
- 13.Del Fabbro M, Afrashtehfar KI, Corbella S, El-Kabbaney A, Perondi I, Taschieri S. In vivo and in vitro effectiveness of rotary nickel-titanium vs manual stainless steel instruments for root canal therapy: systematic review and meta-analysis. J Evid Based Dent Pract. 2018;18:59–69. doi: 10.1016/j.jebdp.2017.08.001. [DOI] [PubMed] [Google Scholar]
- 14.Makanjuola JO, Umesi DC, Oderinu OH. Treatment outcome in rotary versus manual techniques in single-visit endodontics. J West African Coll Surg. 2018;8:44–75. [PMC free article] [PubMed] [Google Scholar]
- 15.Patil AA, Joshi SB, Bhagwat SV, Patil SA. Incidence of postoperative pain after single visit and two visit root canal therapy: a randomized controlled trial. J Clin Diagn Res. 2016;10:9–12. doi: 10.7860/JCDR/2016/16465.7724. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Mayhew D, Mendonca V, Murthy BVS. A review of ASA physical status – historical perspectives and modern developments. Anaesthesia. 2019;74:373–379. doi: 10.1111/anae.14569. [DOI] [PubMed] [Google Scholar]
- 17.Varkevisser CM, Pathmanathan I, Brownlee A. International Development Research Centre;; Amsterdam: 2003. Designing and conducting health systems research projects, volume 1, proposal development and fieldwork; p. 216. [Google Scholar]
- 18.Wei X, Lin SP. The effect of root canal preparation with nickel-titanium rotary instruments in reducing post-operative pain. West China J Stomatol. 2003;21:202–204. [PubMed] [Google Scholar]
- 19.Wong DL, Hockenberry-Easton M, Wilson D, Winkelstein ML, Schwartz P. 6th ed. Mosby Elsevier;; St Louis: 2001. Wong's essentials of paediatric nursing; p. 1301. [Google Scholar]
- 20.Aminoshariae A, Mackey SA, Palomo L, Kulild JC. Declassifying mobility classification. J Endod. 2020;46:1539–1544. doi: 10.1016/j.joen.2020.07.030. [DOI] [PubMed] [Google Scholar]
- 21.Fayad MI, Nair M, Levin MD, et al. AAE and AAOMR joint position statement: use of cone beam computed tomography in endodontics 2015 update. Oral Surg Oral Med Oral Pathol Oral Radiol. 2015;120:508–512. doi: 10.1016/j.oooo.2015.07.033. [DOI] [PubMed] [Google Scholar]
- 22.Molander A, Warfvinge J, Reit C, Kvist T. Clinical and radiographic evaluation of one-and two-visit endodontic treatment of asymptomatic necrotic teeth with apical periodontitis: a randomized clinical trial. J Endod. 2007;33:1145–1148. doi: 10.1016/j.joen.2007.07.005. [DOI] [PubMed] [Google Scholar]
- 23.Huumonen S, Ørstavik D. Radiographic follow-up of periapical status after endodontic treatment of teeth with and without apical periodontitis. Clin Oral Investig. 2013;17:2099–2104. doi: 10.1007/s00784-013-0926-2. [DOI] [PubMed] [Google Scholar]
- 24.Molven O, Halse A, Fristad I, MacDonald-Jankowski D. Periapical changes following root-canal treatment observed 20-27 years postoperatively. Int Endod J. 2002;35:784–790. doi: 10.1046/j.1365-2591.2002.00568.x. [DOI] [PubMed] [Google Scholar]
- 25.Siqueira JF., Jr. Microbial causes of endodontic flare-ups. Int Endod J. 2003;36:453–463. doi: 10.1046/j.1365-2591.2003.00671.x. [DOI] [PubMed] [Google Scholar]
- 26.Mittal R, Singla MG, Garg A, Dhawan A. A comparison of apical bacterial extrusion in manual, ProTaper rotary, and one shape rotary instrumentation techniques. J Endod. 2015;41:2040–2044. doi: 10.1016/j.joen.2015.09.002. [DOI] [PubMed] [Google Scholar]
- 27.Kalra P, Rao A, Suman E, Shenoy R, Suprabha BS. Evaluation of conventional, protaper hand and protaper rotary instrumentation system for apical extrusion of debris, irrigants and bacteria-an in vitro randomized trial. J Clin Exp Dent. 2017;9:254–258. doi: 10.4317/jced.53340. [DOI] [PMC free article] [PubMed] [Google Scholar]
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