Introduction
Materials and methods
Sample
Collection of data
Radiographic evaluation
Periapical status
Outcome measures
Statistical analysis
Category | Covariables | Subgroups |
N (%) |
p value from individual test on covariable | ||
---|---|---|---|---|---|---|
Healing outcome | Tooth survival | |||||
Socio-economic | Age | Below 25 years | 247 (27.8) | <0.001 | <0.001 | |
25–50 years | 444 (50.0) | |||||
Above 50 years | 198 (22.2) | |||||
Gender | Male | 358 (40.3) | 0.003 | 0.032 | ||
Female | 531 (59.7) | |||||
Pre-operative | General health (N = 863; missing 26) | Healthy | 580 (67.2) | 0.428 | 0.027 | |
Not healthy | 283 (32.8) | |||||
Tooth location | Maxilla | 512 (57.6) | 0.026 | 0.089 | ||
Mandible | 377 (42.4) | |||||
Tooth type | Anteriors | 336 (37.8) | <0.001 | 0.005 | ||
Premolars | 268 (30.1) | |||||
Molars | 285 (32.1) | |||||
Pre-operative signs or symptoms | Absent | 401 (45.1) | 0.248 | 0.653 | ||
Present | 488 (54.9) | |||||
Pre-operative pulpal status | Non-vital | 548 (65.6) | 0.010 | 0.026 | ||
Vital | 288 (34.4) | |||||
Pre-operative periapical status | No radiolucency | 516 (58.0) | <0.001 | 0.002 | ||
≤5 mm | 266 (29.9) | |||||
>5 mm | 107 (12.1) | |||||
Intra-operative | Operator status | Undergraduate students | 629 (70.8) | 0.029 | 0.054 | |
Qualified dentists | 260 (29.2) | |||||
Number of visits (N = 888; missing 1) | 1 visit | 27 (3.0) | <0.001 | <0.001 | ||
2 visits | 301 (33.9) | |||||
3 visits | 301 (33.9) | |||||
≥4 visits | 259 (29.2) | |||||
Acute flare-up during treatment (N = 846; missing 43) | Absent | 792 (93.6) | 0.892 | 0.490 | ||
Present | 54 (6.4) | |||||
Extent of root filling (N = 870; missing 19) | Flush (0–2 mm) | 675 (77.6) | <0.001 | <0.001 | ||
Short (>2 mm) | 107 (12.3) | |||||
Overextension | 88 (10.1) | |||||
Extrusion of root filling; including sealer (N = 855; missing 34) | Absent | 721 (84.3) | <0.001 | 0.006 | ||
Present | 134 (15.7) | |||||
Homogeneity of root filling (N = 883; missing 1) | No apparent voids | 432 (48.9) | <0.001 | 0.009 | ||
Voids in apical third | 252 (28.5) | |||||
Voids in middle or coronal third | 199 (22.6) | |||||
Root filling profile (N = 882; missing 7) | Follow original canal form | 721 (81.7) | <0.001 | 0.101 | ||
Sign(s) of ledging, transportation, deviation, broken instrument, or perforation | 161 (18.3) | |||||
Post-operative | Function (N = 875; missing 14) | Presence of both proximal contacts | 576 (65.8) | 0.003 | <0.001 | |
Presence of ≤1 proximal contact | 128 (14.6) | |||||
Cantilever/fixed-fixed/fixed-movable bridge abutment | 68 (7.8) | |||||
Denture/overdenture abutment | 103 (11.8) | |||||
Occlusion (N = 860; missing 29) | No opposing teeth, or opposing denture | 76 (8.9) | 0.112 | 0.017 | ||
Opposing natural teeth | 733 (85.2) | |||||
Opposing fixed prosthesis | 51 (5.9) | |||||
Post (N = 885; missing 4) | Absent | 342 (38.6) | <0.001 | <0.001 | ||
Present | 543 (61.4) | |||||
Type of final restoration (N = 831; missing 58) | Amalgam | 189 (22.7) | <0.001 | <0.001 | ||
Composite resin or GIC | 151 (18.2) | |||||
Indirect cuspal coverage restoration | 476 (57.3) | |||||
Others | 15 (1.8) | |||||
Time to the placement of final restoration (N = 700; missing 189) | ≤2 months | 270 (38.6) | 0.002 | <0.001 | ||
>2–10 months | 284 (40.6) | |||||
>10 months | 146 (20.8) | |||||
Condition of tooth/restoration margin | Satisfactory | 679 (76.4) | <0.001 | <0.001 | ||
Unsatisfactory | 210 (23.6) |
Results
Reasons for exclusion | No. of teeth | Remarks |
---|---|---|
Mismatch of information with patients’ records | 7 | Entry errors in the original patient records |
Periapical surgery pre-planned as part of root canal treatment | 6 | |
Patient never returned for any review | 9 | |
Retreatment cases, instead of primary root canal treatment | 4 | Entry errors |
Right censoring <4 years | 31 | Last available review date <4 years without any observation of post-treatment disease or loss of tooth survival; and patient never returned again |
Multiple teeth treated for a patient | 49 | Only one tooth, randomly selected, was included for each patient |
Incomplete review information, including uncertain healing
| 2 | |
Teeth survived for less than 2 weeks after root canal treatment | 2 | Observation of post-treatment disease or loss of tooth survival within 2 weeks |
Total number of teeth excluded (initial sample = 999) | 110 | A total of 889 teeth were suitable for analysis |
Reasons for failure
Outcome measure | Reasons | ≤40 months | ≥40 months | Total (% of total 889 cases) |
---|---|---|---|---|
Post-treatment disease (clinical plus radiographic) | Periapical periodontitis | 180 | 466 | 646 (72.2) |
Emerging | 38 | 98 | 136 (15.3) | |
Persistent or progressive | 142 | 368 | 510 (57.4) | |
Loss of tooth survival | Clinical signs and symptoms | 85 | 170 | 255 (28.7) |
Extraction | 74 | 162 | 236a (26.5) | |
Failed RCT | 19 | 19 | 38 (4.3) | |
Fractures—root | 26 | 54 | 80 (9.0) | |
Fractures—crown | 9 | 27 | 36 (4.0) | |
Periodontal reasons | 10 | 19 | 29 (3.3) | |
Others | 10 | 43 | 53 (6.0) |
Factors affecting outcome
Factors | Periapical healing | Tooth survival | ||
---|---|---|---|---|
Hazard ratioa (95% CI) |
p value | Hazard ratioa (95% CI) |
p value | |
Age | <0.001 | <0.001 | ||
<25 years | 0.48 (0.36, 0.64) | 0.39 (0.27, 0.55) | ||
25–50 years | 0.64 (0.50, 0.82) | 0.60 (0.45, 0.79) | ||
>50 years | 1 | 1 | ||
Tooth type | 0.007 | <0.001 | ||
Anteriors | 0.71 (0.53, 0.95) | 0.72 (0.52, 1.00) | ||
Premolars | 0.66 (0.50, 0.86) | 0.52 (0.38, 0.71) | ||
Molars | 1 | 1 | ||
Pre-operative periapical status | <0.001 | 0.003 | ||
No lesion | 0.60 (0.44, 0.80) | 0.63 (0.44, 0.89) | ||
≤5 mm | 0.84 (0.61, 1.14) | 0.92 (0.64, 1.33) | ||
>5 mm | 1 | 1 | ||
Occlusion | 0.028 | 0.004 | ||
Non-opposing/opposing denture | 1 | 1.66 (0.82, 3.33) | ||
Opposing (natural teeth) | 1.61 (1.12, 2.32) | 2.45 (1.35, 4.46) | ||
Opposing (fixed prosthesis) | 1.30 (0.77, 2.19) | 1 | ||
Extent of root filling | 0.041 | Not significant | NS | |
Flush | 0.68 (0.49, 0.93) | |||
Short | 0.84 (0.57, 1.23) | |||
Overextended | 1 | |||
Homogeneity of root filling | 0.008 | Not significant | NS | |
No voids, apparently | 0.76 (0.59, 0.98) | |||
Homogenous | ||||
Voids in apical third | 1.08 (0.83, 1.41) | |||
Voids in middle/coronal third | 1 | |||
Number of visits | Not significant | NS | 0.036 | |
1 | 0.63 (0.29, 1.39) | |||
2 | 0.64 (0.47, 0.88) | |||
3 | 0.86 (0.65, 1.14) | |||
4 or more | 1 | |||
Type of final restoration | <0.001 | <0.001 | ||
Amalgam | 1 | 1 | ||
Composite/GIC | 0.69 (0.49, 0.97) | 0.70 (0.47,, 1.03) | ||
Indirect cuspal coverage | 0.51 (0.40, 0.65) | 0.41 (0.31, 0.55) | ||
Restoration | ||||
Others | 1.73 (0.85, 3.52) | 1.36 (0.65, 2.84) | ||
Condition of the tooth/restoration margin | <0.001 | <0.001 | ||
Satisfactory | 0.63 (0.51, 0.79) | 0.47 (0.36, 0.60) | ||
Unsatisfactory | 1 | 1 |