Prevalence and determinants of clinical and radiographic outcomes of endodontic treatment at Jimma Medical Center: an ambispective single-cohort study

Abstract

Background

Endodontic treatment is fundamental to preserving teeth affected by pulpal and periapical diseases. Robust evidence on treatment outcomes and their determinants is essential for optimizing clinical practice, yet data from sub-Saharan Africa remain scarce. This study assessed the prevalence, clinical and radiographic outcomes, and determinants of endodontic treatment success and failure among patients treated at Jimma Medical Center (JMC), Ethiopia.

Methods

An ambispective single-cohort study was conducted among a sample of 404 patients who received endodontic treatment at JMC from September 1, 2025, to November 30, 2025. Data were collected on socio-demographics, preoperative clinical and radiographic characteristics, procedural details, and patient-reported outcomes. Clinical and radiographic success was assessed using the Periapical Index (PAI) and symptom resolution. Logistic regression analyses were performed to identify determinants of treatment outcomes, with adjusted odds ratios (AORs) and 95% confidence intervals (CIs) estimated, and statistical significance set at p < 0.05.

Results

The majority of participants were aged 25–44 years (49.6%) and female (55.8%), with an overall treatment success rate of 84.2%. Most teeth were non-vital (96.4%) and presented with symptomatic pulpitis or apical periodontitis. Irrigation was primarily performed with saline (85.2%), and optimal obturation quality was achieved in 90.1% of cases. At follow-up, 84.2% of teeth were classified as successful, defined as absence of symptoms and PAI ≤ 2, while 15.8% failed. The most frequent causes of failure were persistent infection (42.6%) and coronal leakage (41.0%). Patient-reported outcomes indicated high satisfaction, with 89.1% of patients reporting satisfaction and 73.0% reporting complete absence of pain post-treatment.

Multivariable logistic regression analysis identified several independent determinants of treatment success. Male patients had 2.86 times higher odds of treatment success than female patients (AOR = 2.86, 95% CI: 1.98–3.53; p < 0.04). Conversely, symptomatic periapical lesions or abscesses were associated with 43% lower odds of treatment success (AOR = 0.57, 95% CI: 0.05–0.86; p < 0.03). Similarly, the use of saline as the primary irrigant was associated with 54% lower odds of treatment success than H₂O₂ alone or saline combined with H₂O₂ (AOR = 0.46, 95% CI: 0.21–0.91; p < 0.04). In addition, a temporary or inadequate coronal seal at treatment completion was associated with 62% lower odds of treatment success than a composite restoration or crown (AOR = 0.38, 95% CI: 0.16–0.88; p < 0.02).

Conclusion

Endodontic treatment at JMC demonstrates a high success rate, with most teeth showing favorable clinical, radiographic, and patient-reported outcomes. Male gender, preoperative periapical pathology, type of primary irrigant, and coronal restoration quality were significant determinants of treatment outcome. These findings underscore the importance of meticulous procedural protocols and proper coronal sealing to enhance treatment success.

Introduction

Endodontic therapy, or root canal treatment (RCT), is a biologically based, evidence-driven procedure designed to eliminate intracanal infection, prevent reinfection, and promote periradicular healing, thereby preserving natural teeth and restoring oral function [1, 2]. When performed according to standardized protocols, nonsurgical RCT achieves success rates of 85–95%, offering a conservative alternative to extraction for managing pulpal and periapical pathology [3]. Despite this high efficacy, clinical outcomes are often variable in routine practice, reflecting the influence of multiple interrelated factors [2, 4].

Preoperative periapical status, particularly the presence of apical periodontitis, strongly predicts prognosis, with necrotic teeth demonstrating lower healing rates than vital teeth [5]. Equally important are technical aspects of treatment: adequate working length, three-dimensional obturation, and absence of voids are critical for periapical healing, whereas procedural errors and missed canals are associated with persistent disease [5, 6]. Post-treatment factors, such as the timing and integrity of coronal restoration, further modulate outcomes by preventing reinfection. Together, these determinants underscore that RCT success is not solely procedure-dependent but also shaped by patient, tooth, and treatment factors [6, 7].

The need for endodontic care is substantial, driven globally by untreated dental caries, which remains highly prevalent [8]. In Ethiopia, caries affects 35–40% of the population, particularly children and adolescents, placing many at risk for pulpal and periapical disease [9, 10]. Yet, utilization of dental services is limited, and patients frequently present with advanced pathology—including irreversible pulpitis, necrotic pulp, or established apical periodontitis—complicating treatment and reducing prognosis [9, 10]. In this context, resource limitations often compel clinicians to adopt pragmatic approaches prioritizing pain relief and infection control over ideal technical standards like Cone-Beam Computed Tomography (CBT) [11], but the effectiveness of these adapted practices remains poorly documented [10, 12]. At JMC, root canal treatments (RCTs) are routinely performed, yet no institution-specific studies have systematically evaluated treatment outcomes, radiographic healing, or factors influencing success. Addressing this gap is essential to inform clinical practice, guide policy, and improve oral health in the population served [13]. Using a conceptual framework (Fig. 1) encompassing patient, tooth, technical, and post-treatment factors, this study aims to determine the prevalence of endodontic disease, assess RCT outcomes, identify predictors of periapical healing [6], and generate evidence to support context-appropriate clinical and policy interventions.

Fig. 1.

Illustrates a conceptual framework of endodontic treatment outcomes at JMC, integrating patient, tooth, technical, and post-treatment factors

Materials and methods

Study area, design and period

An ambispective single-cohort study was conducted at the Dental Department of Jimma Medical Center (JMC), a tertiary referral and teaching hospital in Jimma City, Oromia, southwestern Ethiopia. The hospital provides comprehensive dental services, including endodontic care, to patients from the city and surrounding catchment areas.

The study combined retrospective record review with a prospective recall assessment. Initially, dental records of patients who had undergone non-surgical root canal treatment (RCT) were reviewed to identify eligible cases and extract baseline patient characteristics, preoperative clinical and radiographic findings, and treatment-related variables. Eligible teeth were those that had received RCT between 1 and 5 years before the recall assessment, thereby ensuring that all cases had a minimum follow-up period of 6 months after treatment. Subsequently, from September 1, 2025, to November 30, 2026, eligible patients were recalled for a single follow-up evaluation. During this visit, participants underwent a standardized clinical examination, periapical radiographic assessment, and structured interview to determine treatment outcomes.

Treatment outcomes at the recall visit were classified using combined clinical and radiographic criteria. Cases with no clinical signs or symptoms (pain, swelling, or sinus tract) and radiographic evidence of complete or incomplete periapical healing, or no progression of a pre-existing periapical radiolucency, were classified as successful. Cases with persistent or newly developed clinical signs and/or symptoms, or radiographic evidence of persistent, enlarging, or newly developed periapical radiolucency, were classified as failures. By linking historical treatment records with findings from the recall examination, the study evaluated the medium-term to long-term outcomes of non-surgical root canal treatment and explored factors associated with treatment success.

Within the clinical setting, endodontic treatment at JMC is provided by undergraduate dental students, postgraduate residents, and specialist endodontists following standardized diagnostic protocols based on patient history, clinical examination, pulp sensibility testing, and radiographic evaluation. Root canal treatment involves chemo-mechanical preparation using stainless steel hand files and nickel–titanium (NiTi) rotary instruments. Due to resource constraints and challenges in the procurement and supply of essential dental materials, normal saline was used as the primary irrigating solution and was occasionally supplemented with 3% hydrogen peroxide. In multi-visit cases, calcium hydroxide was used as an intracanal medicament between appointments. Similarly, all treatments were performed under cotton-roll isolation with saliva ejectors, as rubber dam isolation was not routinely available due to the same resource-related constraints during the study period. Obturation was completed using gutta-percha and the cold lateral condensation technique, followed by coronal restoration with composite resin. Full-coverage crowns were provided when clinically indicated. Particular emphasis was placed on achieving an adequate coronal seal because of its recognized importance for long-term endodontic success.

Study population

The target population comprised all patients who received primary non-surgical root canal treatment (RCT) on permanent teeth at the Dental Department of Jimma Medical Center 1–5 years prior to the study. Teeth and patients were included if the RCT was initiated and completed entirely at JMC, treatment fell within the specified timeframe, adequate clinical records and diagnostically acceptable pre- and postoperative radiographs were available, the treated tooth had a permanent coronal restoration at the time of assessment, and the patient (or legal guardian) provided written informed consent. Exclusion criteria included incomplete RCT, teeth undergoing or previously treated with endodontic retreatment, third molars, radiographs of insufficient quality for periapical evaluation, and patients who could not be contacted, declined participation, or had incomplete clinical records. These criteria ensured the selection of a representative, well-documented cohort suitable for reliable evaluation of treatment outcomes and determinants.

Sample size determination and sampling technique

The sample size was determined using the single population proportion formula appropriate for cross-sectional epidemiological studies estimating a single population parameter. In the absence of prior local data on endodontic treatment success at Jimma Medical Center, a conservative proportion of 50% was assumed to maximize variability and ensure adequate precision. Using StatCalc with a 95% confidence level (Z = 1.96) and a margin of error of 5%, the initial calculated sample size was 384 participants. To preserve statistical validity and account for a potential 5% non-response rate, the sample size was adjusted upward, resulting in a final required sample of 404 participants. Regarding the sampling technique, eligible participants were selected using a simple random sampling method from the sampling frame of patients who underwent endodontic treatment during the study period. Recruitment continued until the calculated sample size of 404 participants was achieved.

Data collection methods, measurements, and outcome variables

Data were collected using a structured and standardized approach from three sources: clinical and radiographic examinations, patient interviews, and dental record abstraction. Standardized data collection forms were used throughout the study, and all examiners underwent training and calibration before data collection to ensure consistency in clinical assessments and radiographic interpretation.

Radiographic outcomes were assessed using standardized periapical radiographs and evaluated according to the Periapical Index (PAI). Prior to the study, examiners were calibrated using a standardized set of reference radiographs. Inter- and intra-examiner agreement for PAI scoring was evaluated using Cohen’s kappa statistic. The inter-examiner kappa value was 0.84, and the intra-examiner kappa value was 0.89, indicating almost perfect agreement in radiographic assessment. Radiographic success was defined as a PAI score ≤ 2, while radiographic failure was defined as a PAI score > 2.

Clinical outcomes were determined by the absence of pain, swelling, sinus tract, tenderness to percussion or palpation, and the presence of normal tooth function. Overall treatment success was defined as the simultaneous presence of radiographic success (PAI ≤ 2) and the absence of clinical signs and symptoms at the recall examination.

Independent variables included: (i) patient-related factors (age, sex, systemic health status, and preoperative symptoms); (ii) tooth-related factors (tooth type, anatomical location, and preoperative periapical status); and (iii) treatment-related factors (operator category, number of treatment visits, quality of root canal obturation, and integrity of the coronal seal). These variables were analyzed to identify factors associated with endodontic treatment outcomes.

Data quality control, processing, and analysis

To ensure data reliability and validity, several quality control measures were implemented. The data collection tools were pilot tested prior to the main study. In addition, examiners underwent calibration for both clinical and radiographic assessments, and inter- and intra-examiner reliability were evaluated using kappa statistics. Data entry was performed using a double-entry procedure, and data quality was further ensured through routine supervision and cross-checking throughout the data collection process.

Data were entered, cleaned, and analyzed using IBM SPSS Statistics version 26. Descriptive statistics were used to summarize participant characteristics, treatment variables, and outcomes. Bivariable logistic regression analysis was conducted to identify candidate variables associated with treatment outcomes, and variables with p < 0.25 were included in the multivariable logistic regression model. Adjusted odds ratios (AOR) with 95% confidence intervals were calculated, and statistical significance was set at p < 0.05.

The final multivariable logistic regression model was assessed for adequacy and underlying assumptions. Multicollinearity was evaluated using variance inflation factor (VIF = 1.12–2.34) and tolerance values (0.43–0.89), indicating no significant collinearity among predictors. Model fitness was confirmed using the Hosmer–Lemeshow test (χ² = 6.48, p = 0.59). The Omnibus test indicated that the model was statistically significant overall (p < 0.001), and it demonstrated acceptable explanatory power (Nagelkerke R² = 0.31). The model also showed an overall classification accuracy of 76.4%, and residual and influence diagnostics confirmed the absence of influential outliers.

Results

Socio-demographic characteristics of respondents

Out of 404 sampled participants, 385 responded, yielding a response rate of 95.3%, indicating minimal non-response rate. The majority of participants were young adults aged 21–40 years (81.8%), with 32.2% aged 21–30 years and 49.6% aged 31–40 years. The least represented age groups were ≤ 20 years (3.6%) and > 50 years (2.9%). Females comprised 55.8% of the sample, while 44.2% were male. Regarding educational attainment, 44.4% had tertiary education, 34.5% secondary, 9.4% primary, and 11.7% had no formal education. Occupation-wise, students were the largest group (37.9%), followed by unemployed participants (23.6%), government employees (23.1%), merchants (8.3%), and farmers (7.0%) (Table 1).

Table 1.

Socio-demographic characteristics of endodontically treated patients (n = 385) at Jimma Medical Center

Variables	Category	Frequency	Percent
Age in years	≤20 years	14	3.6
	21–30 years	124	32.2
	31–40 years	191	49.6
	41–50 years	45	11.7
	> 50 years	11	2.9
Sex	Male	170	44.2
	Female	215	55.8
Education level	No formal education	45	11.7
	Primary	36	9.4
	Secondary	133	34.5
	Tertiary	171	44.4
Occupational category	Farmer	27	7.0
	Student	146	37.9
	Government	89	23.1
	Merchant	32	8.3
	Unemployed	91	23.6

Preoperative clinical and radiographic characteristics of teeth

The majority of teeth were non-vital, with 47.3% necrotic and 49.1% exhibiting irreversible pulpitis, while 3.6% were vital. Preoperative periapical assessment showed normal status in 49.1% of teeth and symptomatic/abscess in 50.9%. Clinically, spontaneous pain was reported in 64.2% of cases, pain on biting in 31.4%, while swelling (0.5%), sinus tract (1.3%), and absence of symptoms (2.6%) were less frequent. Radiographically, 56.6% of teeth had a normal PAI score, 31.2% were PAI 2, 10.1% PAI 3, 1.8% PAI 4, and 0.3% PAI 5. Root canals were predominantly straight (60.3%), with 39.7% showing moderate curvature. Overall, the sample was characterized by predominantly non-vital teeth with symptomatic presentation, mostly straight canals, and a higher proportion of molars (Table 2).

Table 2.

Preoperative clinical, radiographic, and anatomical characteristics of teeth

Variables	Category	Frequency	Percent
Any medical systemic morbidity	Yes	75	19.5
	No	310	80.5
Preoperative Pulp Status	Vital	14	3.6
	Necrotic	182	47.3
	Irreversible pulpitis	189	49.1
Preoperative Periapical status	Normal	189	49.1
	Symptomatic /Abscess	196	50.9
Preoperative clinical Symptoms	Spontaneous pain	247	64.2
	Pain on biting	121	31.4
	Swelling	2	0.5
	Sinus tract	2	1.3
	None	13	2.6
Preoperative Radiographic status (Periapical Index - PAI Score)	PAI 1 (Normal)	218	56.6
	PAI 2	120	31.2
	PAI 3	39	10.1
	PAI 4	7	1.8
	PAI 5 (Large Lesion)	1	0.3
Root complexity	Straight	232	60.3
	Moderate Curvature (> 10°)	153	39.7

Clinical and procedural characteristics of endodontic treatment

Among the 385 teeth treated at Jimma Medical Center, the majority were irrigated primarily with saline (85.2%), followed by a combination of saline and hydrogen peroxide (14.8%), while other irrigants were not reported. For the final rinse, most teeth received no additional irrigant (82.6%), whereas EDTA was used in 17.4% of cases.

Intracanal medicaments were applied in 14.8% of teeth using calcium hydroxide, while 85.2% received none. The quality of obturation was generally high: 79.0% of canals were filled optimally (± 2 mm from apex), with 21.0% underfilled or overfilled. Homogeneous obturation density was observed in 80.0% of teeth, while 20.0% showed voids. Adequate canal taper was achieved in 83.1% of cases. Coronal sealing at completion was predominantly with composite restorations or crowns (81.6%), while 18.4% received temporary or inadequate restorations. Overall, these findings indicate that endodontic procedures at this center exhibit high standards in obturation, canal taper, and coronal sealing, with some variability in irrigant and medicament use (Table 3).

Table 3.

irrigation, intracanal medicament, obturation quality, and coronal seal characteristics of endodontic treatment (n = 385) at Jimma Medical Center

Variable	Category	Frequency	Percent
Primary Irrigant	Saline	328	85.2
	Saline and H2O2	57	14.8
Final rinse	EDTA	67	17.4
	None	318	82.6
Intracanal Medicament	Ca (OH)2	57	14.8
	None	328	85.2
Obturation length	Optimal (± 2 mm apex	304	79.0
	Underfilled/Overfilled	81	21.0
Density	Homogeneous	308	80.0
	Voids Present	77	20.0
Taper	Adequate	320	83.1
	Inadequate	65	16.9
Coronal Seal at Completion	Temporary/inadequate	71	18.4
	Composite/ Crown	314	81.6

Clinical characteristics and radiographic outcomes (n = 385)

Among the 385 endodontically treated teeth evaluated at Jimma Medical Center, the majority were asymptomatic at the time of examination, accounting for 81.3% of cases. Pain was the most frequently reported symptom, affecting 16.4% of teeth, whereas swelling (1.3%), sinus tract formation (0.5%), and tenderness to percussion (0.5%) were relatively rare. Regarding coronal restoration status, most teeth had intact restorations (62.1%), while fractured restorations were observed in 36.6% of cases; recurrent caries (0.3%) and marginal gaps (1.0%) were uncommon. Radiographic assessment using the Periapical Index (PAI) revealed that 81.8% of teeth exhibited complete periapical healing (PAI 1), 8.3% had PAI 2 lesions, 9.1% had PAI 3 lesions, and high-grade lesions (PAI 4–5) were rare, representing only 0.8% of cases. Overall, 84.2% of teeth were classified as successful (absence of clinical symptoms and PAI ≤ 2), whereas 15.8% were considered failures (PAI ≥ 3 or presence of symptoms). These results indicate that most endodontically treated teeth in this cohort demonstrated favorable clinical and radiographic outcomes, with treatment failure primarily associated with persistent infection and compromised coronal restorations (Table 4).

Table 4.

Clinical, radiographic, and restorative outcomes of treated teeth (n = 385) at Jimma Medical Center

variables	category	Frequency	Percent
Clinical Symptoms at examination	Pain	63	16.4
	Swelling	5	1.3
	Sinus Tract	2	0.5
	Tenderness to Percussion	2	0.5
	None	313	81.3
Coronal Restoration Status at examination	Intact	239	62.1
	Fractured	141	36.6
	Recurrent Caries	1	0.3
	Marginal Gap	4	1.0
Radiographic Healing at Examination (Periapical Index - PAI Score)	PAI 1	315	81.8
	PAI 2	32	8.3
	PAI 3	35	9.1
	PAI 4	1	0.3
	PAI 5	2	0.5
Overall Healing Classification (Success/Failure)	Success (PAI = 2 + No Symptoms + F	324	84.2
	Failure (PAI = 3 OR Symptoms Present	61	15.8

Prevalence and contributing factors of endodontic treatment outcomes

Among the 385 patients enrolled in the study, treatment outcomes were assessed to determine overall success and failure rates of endodontic therapy. The results showed that 84.2% of cases achieved successful healing, while 15.8% (n = 61) were classified as treatment failures. Among the failed cases, the most frequently identified contributing factors were persistent infection (42.6%) and coronal leakage (41.0%). Less common causes included inadequate root canal filling (8.2%) and vertical root fracture (8.2%). Overall, these findings demonstrate a high success rate of endodontic treatment, with biological factors and deficiencies in coronal restoration emerging as the principal determinants of failure (Fig. 2).

Fig. 2.

Prevalence and contributing factors of endodontic treatment outcomes among patients treated (n = 385) at Jimma Medical Center

Patient-reported endodontic treatment outcomes

Overall, 343 patients (89.1%) reported being satisfied with their treatment, with 202 patients (52.5%) being very satisfied and 141 patients (36.6%) satisfied. A small proportion reported neutral or negative experiences, with 19 patients (4.9%) feeling neutral, 22 patients (5.7%) dissatisfied, and 1 patient (0.3%) very dissatisfied. Before treatment, the vast majority of patients (357, 92.7%) experienced severe pain, while 24 patients (6.2%) reported moderate pain and 4 patients (1.0%) had mild pain. Following treatment, pain levels significantly decreased: 281 patients (73.0%) reported no pain, 33 patients (8.6%) mild pain, 48 patients (12.5%) moderate pain, and only 23 patients (6.0%) continued to experience severe pain. Most participants (322, 83.6%) expressed willingness to choose root canal treatment again if needed. Only 23 patients (6.0%) said they would not, and 40 patients (10.4%) were unsure (Table 5).

Table 5.

Patient-reported outcomes (n = 385) following endodontic treatment at JMC

Variable	Category	Frequency	Percent
Patient Satisfaction with Treatment	Very satisfied	202	52.5
	Satisfied	141	36.6
	Neutral	19	4.9
	Dissatisfied	22	5.7
	Very dissatisfied	1	0.3
Degree of pain before treatment	Severe	357	92.7
	Moderate	24	6.2
	Mild	4	1.0
Degree of pain After treatment	Severe	23	6.0
	Moderate	48	12.5
	Mild	33	8.6
	None	281	73.0
Patient Willingness to Choose Root Canal Treatment Again	Yes	322	83.6
	No	23	6.0
	Not sure	40	10.4

Determinants of endodontic treatment outcome

Bivariable logistic regression analysis was performed to identify potential determinants of endodontic treatment outcomes. Variables with a p-value < 0.25 in the bivariable analysis were considered for inclusion in the multivariable logistic regression model to adjust for potential confounding. Accordingly, age, gender, education level, medical history, pulp status, periapical status, preoperative symptoms, preoperative radiographic findings (periapical index [PAI]), root complexity, primary irrigant, final rinse, obturation length, density, taper, and coronal seal at completion were entered into the multivariable model.

In the multivariable logistic regression analysis, gender, periapical status, primary irrigant, and coronal seal at treatment completion were independently associated with treatment success. Male patients had 2.86 times higher odds of treatment success than female patients (AOR = 2.86, 95% CI: 1.98–3.53; p < 0.04). In contrast, teeth presenting with symptomatic periapical lesions or abscesses had 43% lower odds of treatment success than those with asymptomatic periapical lesions (AOR = 0.57, 95% CI: 0.05–0.86; p < 0.03). Likewise, the use of saline as the primary irrigant was associated with a 54% reduction in the odds of treatment success compared with the use of H₂O₂ alone or saline combined with H₂O₂ (AOR = 0.46, 95% CI: 0.21–0.91; p = 0.04). Additionally, teeth restored with a temporary or inadequate coronal seal at treatment completion had 62% lower odds of treatment success than those restored with a composite restoration or crown (AOR = 0.38, 95% CI: 0.16–0.88; p < 0.02).

Other variables, including age, education level, medical history, pulp status, preoperative symptoms, preoperative radiographic findings (PAI), root complexity, final rinse protocol, obturation length, density, and taper, were not significantly associated with treatment outcomes (p > 0.05). Overall, these findings indicate that gender, periapical status, type of primary irrigant, and quality of coronal seal at completion are independent determinants of endodontic treatment success (Table 6).

Table 6.

Determinants of endodontic treatment outcome (n = 385) at JMC

Variable	Category	Treatment outcomes		Bivariable Analysis		Multivariable Analysis
		Success (n = 324)	Failure (n = 61)	P-value	COR (95% CI)	P-value	AOR (95% CI)
Age	≤20 years	12	2	0.30	1.01 (0.99–1.04)	0.28	1.02 (0.99–1.05)
	21–30 years	104	20	0.40	1.12 (0.78–1.61)	0.35	1.09 (0.74–1.60)
	31–40 years	161	30	0.50	1.00	0.50	1.00
	41–50 years	38	7	0.85	0.98 (0.57–1.69)	0.87	0.97 (0.55–1.70)
	> 50 years	9	2	0.90	0.95 (0.31–2.87)	0.91	0.96 (0.32–2.90)
Gender	Male	140	30	0.17	1.49 (0.85–2.60)	0.04	2.86 (1.98–3.53) *
	Female	184	31	0.21	1.00	0.08	1.00
Education level	No formal education	36	9	0.09	1.37 (0.95–1.96)	0.09	1.37 (0.95–1.96)
	Primary	32	4	0.70	1.10 (0.67–1.80)	0.72	1.12 (0.68–1.84)
	Secondary	110	23	0.50	1.00	0.50	1.00
	Tertiary	146	25	0.80	0.95 (0.65–1.39)	0.82	0.97 (0.66–1.41)
Medical Systemic Morbidity	Yes	60	15	0.04	0.73 (0.54–0.98)	0.06	0.73 (0.53–1.01)
	No	264	46	0.50	1.00	0.50	1.00
Preoperative Pulp Status	Vital	12	2	0.28	0.71 (0.39–1.28)	0.52	1.24 (0.65–2.37)
	Necrotic	154	28	0.50	1.00	0.50	1.00
	Irreversible pulpitis	158	31	0.75	1.08 (0.67–1.74)	0.52	1.12 (0.69–1.80)
Periapical Status	Asymptomatic	153	43	0.50	1.00	0.50	1.00
	Symptomatic/ Abscess	171	18	0.02	0.47 (0.15–0.90)	0.03	0.57 (0.05–0.86) *
Preoperative clinical Symptoms	Spontaneous pain	212	35	0.18	1.25 (0.90–1.73)	0.47	1.14 (0.79–1.65)
	Pain on biting	100	21	0.70	1.10 (0.68–1.78)	0.47	1.08 (0.66–1.75)
	Swelling	2	0	0.97	0.98 (0.20–4.72)	0.47	1.05 (0.21–5.25)
	Sinus tract	2	0	0.97	0.98 (0.20–4.72)	0.47	1.05 (0.21–5.25)
	None	8	5	0.50	1.00	0.50	1.00
Preoperative Radiographic Findings (PAI)	PAI 1	180	18	0.04	1.42 (1.03–1.97)	0.86	1.05 (0.61–1.82)
	PAI 2–5	144	43	0.50	1.00	0.50	1.00
Root Complexity	Straight	200	32	0.58	1.19 (0.64–2.24)	0.58	1.19 (0.64–2.24)
	Moderate curvature	124	29	0.50	1.00	0.50	1.00
Primary Irrigant	Saline	276	52	0.12	0.58 (0.29–1.14)	0.04	0.46 (0.21–0.91) *
	H₂O₂ / Saline + H₂O₂	48	9	0.50	1.00	0.50	1.00
Final Rinse	None	318	60	0.14	0.27 (0.05–1.51)	0.14	0.27 (0.05–1.51)
	NaOCl / EDTA	6	1	0.50	1.00	0.50	1.00
Obturation Length	Optimal	304	43	0.41	1.31 (0.69–2.50)	0.41	1.31 (0.69–2.50)
	Underfilled / Overfilled	20	18	0.50	1.00	0.50	1.00
Density	Homogeneous	308	55	0.15	2.76 (0.69–11.16)	0.15	2.76 (0.69–11.16)
	Voids	16	6	0.50	1.00	0.50	1.00
Taper	Adequate	320	56	0.95	1.05 (0.20–5.54)	0.95	1.05 (0.20–5.54)
	Inadequate	65	5	0.50	1.00	0.50	1.00
Coronal Seal at Completion	Temporary / Inadequate	71	8	0.01	0.35 (0.15–0.81)	0.02	0.38 (0.16–0.88) *
	Composite / Crown	314	53	0.50	1.00	0.50	1.00

Discussion

This study, conducted at Jimma Medical Center, provides insight into the outcomes and determinants of non-surgical root canal treatment (RCT) in a resource-limited teaching hospital setting. Using an ambispective single-cohort design, the findings reflect both historical clinical records and contemporary post-treatment evaluations, offering a comprehensive perspective on endodontic treatment performance in routine practice conditions. The overall success rate of 84.2%—defined by combined clinical and radiographic criteria—is consistent with the lower range of success reported in the global endodontic literature (85–95%) for primary nonsurgical RCT [2]. Although this outcome affirms that clinically acceptable healing is attainable in a constrained setting, it also highlights opportunities for improvement, particularly considering that many specialist and high-resource centers routinely report success rates above 90% [2, 12, 14]. Compared to studies using strict clinical-radiographic criteria in well-resourced environments, this success rate is modest. For instance, Ng et al. reported pooled healing rates of 86–95% for primary RCT with high-quality technical standards and optimal irrigation protocols [2], while large retrospective studies from university clinics in developed settings demonstrate healing rates consistently in the high 80s to mid-90s percentiles [15, 16]. Our findings align more closely with those reported in other African and resource-limited settings, where success rates generally range from 70% to the mid-80%, highlighting the influence of contextual constraints on treatment outcomes [17–19]. A potential contributing factor was the use of substandard irrigation protocols, with canal irrigation performed primarily using normal saline alone or supplemented with 3% hydrogen peroxide because sodium hypochlorite (NaOCl) was unavailable due to procurement and supply-chain limitations. As these irrigants have lower antimicrobial efficacy and tissue-dissolving capacity than NaOCl, their use may have contributed to the comparatively lower treatment success and higher failure rates observed in this study. Likewise, procedures were performed under cotton-roll isolation with saliva ejectors rather than rubber dam isolation, which may have further compromised aseptic control and contributed to reduced treatment success [20].

Among the factors analyzed, preoperative periapical status emerged as a consistent and biologically plausible determinant of outcome. Teeth with normal periapical tissues had significantly higher odds of success than those with symptomatic apical periodontitis or abscess (AOR = 1.57; p < 0.03), corroborating literature that periapical lesions represent a higher microbial burden and structural challenge to chemo-mechanical disinfection [5, 6, 21]. Pulpal necrosis and chronic apical periodontitis have been repeatedly associated with decreased radiographic healing compared to vital pulps [5, 22]. Biologically, these lesions often reflect established biofilm colonization beyond the root apex, involving resistant species such as Enterococcus faecalis and anaerobes. Without advanced disinfection strategies, eradication of these pathogens is difficult, explaining the relative reduction in success observed [23]. Patient satisfaction.

Procedural variables also played a crucial role in treatment outcomes. The use of normal saline as the primary irrigant was associated with significantly lower success compared to protocols involving hydrogen peroxide (AOR = 0.46; p < 0.04), underscoring the importance of irrigant selection in endodontic disinfection. Although saline is biocompatible and widely used, it lacks both antimicrobial activity and tissue-dissolving capacity, limiting its effectiveness in removing necrotic debris and eliminating intracanal microorganisms. In contrast, sodium hypochlorite (NaOCl)—the gold standard irrigant—provides both potent antimicrobial action and organic tissue dissolution, making it superior for achieving effective chemomechanical debridement [24, 25]. Accordingly, international guidelines recommend NaOCl at concentrations of 2.5–5.25% for primary root canal treatment to optimize microbial reduction and healing outcomes [13, 26], and evidence consistently shows its superiority over saline and other weak irrigants.

The reliance on saline in this setting likely reflects resource limitations and may have contributed to inadequate chemical disinfection, leaving residual infected tissue and biofilm, as reflected in the 42.6% persistent infection among failed cases [27, 28]. Persistent infection remains a key cause of endodontic failure and is strongly associated with biofilm-forming organisms, particularly Enterococcus faecalis, which can survive harsh intracanal conditions, resist antimicrobials, and persist within dentinal tubules. In the absence of effective irrigants like NaOCl, these organisms can survive within protected niches such as isthmuses, lateral canals, and dentinal tubules, contributing to reinfection [29]. moderate curvature.

Moreover, suboptimal antimicrobial exposure may enhance biofilm resilience; Bernardi et al. showed that subinhibitory antimicrobial concentrations can stimulate E. faecalis biofilm formation and increase tolerance to subsequent treatment [29]. Although based on antibiotics, this supports the broader concept that inadequate antimicrobial strategies may promote more resistant biofilm phenotypes. Collectively, these findings indicate that persistent intraradicular infection is not simply a failure of mechanical debridement but a complex biofilm-mediated process strongly influenced by the effectiveness of irrigating solutions [27, 28].

The quality of the coronal seal at completion was a significant determinant of treatment outcome (AOR = 0.38; p < 0.02). Teeth with inadequate or temporary restorations showed higher odds of failure, confirming that coronal leakage may compromise long-term success more than root filling quality alone [6]. Evidence from subsequent studies similarly emphasizes the role of definitive restorations in preventing post-treatment microbial ingress [26–28]. In this cohort, 36.6% of treated teeth exhibited fractured restorations at recall, indicating that restorative breakdown is a key post-treatment failure mechanism rather than a simple follow-up finding [30]. This highlights the need to view coronal restoration status as a dynamic prognostic factor, where long-term restoration survival is as critical as initial seal quality [3]. Fractured restorations may permit microleakage and reinfection, contributing to late endodontic failure. The high fracture rate likely reflects limited use of cuspal coverage in posterior teeth, which are more susceptible to occlusal stress. Consistent evidence shows that posterior endodontically treated teeth without cuspal protection have lower survival and higher fracture risk compared with crowned teeth. Therefore, post-endodontic restorative strategy plays a decisive role in long-term outcomes and should be considered an integral determinant of treatment success rather than a secondary factor [31].

Although obturation length, density, and taper are recognized technical factors influencing periapical healing [12], they were not statistically significant in the multivariable analysis. While 79.0% of teeth demonstrated optimal obturation length and 80.0% showed homogeneous density, the presence of voids and occasional over- or underfillings may still contribute to persistent infection. Prior studies indicate that voids act as niduses for residual bacteria and compromise mechanical sealing [32]. The absence of statistical association in this cohort may reflect insufficient power to detect modest effects or confounding from irrigation and restoration quality, which exert more dominant influences.

Patient-related factors also influenced treatment outcomes. In the present study, male patients had significantly higher odds of favorable endodontic treatment outcomes than female patients (AOR = 2.86, p < 0.04). Although sex has not been consistently identified as an independent determinant of endodontic treatment success in previous studies, some investigations have suggested that patient-related sociodemographic characteristics may influence endodontic prognosis [33, 34]. The mechanisms underlying the observed association remain uncertain and are unlikely to be attributable to biological sex alone. Rather, the association may reflect differences in behavioral, social, and healthcare-related factors that were not assessed in the present study. Potential contributors include variations in oral health behaviors, adherence to treatment recommendations, utilization of dental services, and attendance at follow-up appointments. In addition, socioeconomic and cultural factors may influence access to care, treatment compliance, and oral health practices, thereby indirectly affecting treatment outcomes. However, because these variables were not measured, the observed association should be interpreted with caution, as residual confounding and unmeasured covariates may have contributed to the findings [35].

Clinical presentation in the present study demonstrated a significant prognostic effect on endodontic healing outcomes, with symptomatic cases (including abscesses) showing significantly lower healing rates than asymptomatic cases (AOR = 0.57, p < 0.03), indicating that preoperative infection negatively influences treatment success. This finding is consistent with earlier and recent evidence, including systematic reviews and cohort studies (2020–2024), which consistently identify preoperative symptoms and apical infection as strong predictors of reduced healing, largely due to increased microbial burden and more advanced periapical disease [36]. Similarly, the literature reports that teeth presenting with apical periodontitis, swelling, or abscess formation generally exhibit lower healing rates than asymptomatic cases, even with contemporary endodontic techniques, reinforcing that baseline periapical status remains a key determinant of prognosis. In contrast, systemic morbidity in the present study showed a non-significant trend toward reduced healing, which is also in agreement with recent studies (2020–2024) suggesting that conditions such as diabetes mellitus may impair immune response and delay periapical repair, but their impact on endodontic outcomes is typically weaker and more variable than local disease factors. The absence of statistical significance in this study may be attributed to the relatively small proportion of medically compromised patients, limiting statistical power to detect differences, a limitation similarly highlighted in previous research [37].

The determinants identified suggest several modifiable targets to improve outcomes at JMC. Routine use of sodium hypochlorite for irrigation, with activation where feasible, should be prioritized to augment antimicrobial efficacy. Improved definitive coronal restoration protocols, including timely placement of cuspal coverage for posterior teeth, should be integrated into treatment planning and supervision. Enhanced preoperative risk assessment, particularly for teeth with symptomatic periapical pathology, can inform case selection, patient counseling, and tailored disinfection strategies. Education and reinforcement of post-treatment maintenance and recall may bridge the gap between technical success and long-term retention.

Strength and limitation of the study

This study’s strengths include its ambispective single-cohort design combining retrospective record review with prospective clinical and radiographic follow-up, which enhanced the comprehensiveness of outcome assessment. Standardized clinical and PAI-based definitions improved measurement reliability, supported by high inter- and intra-examiner agreement, while multivariable regression analysis strengthened the identification of independent determinants of treatment outcomes by adjusting for potential confounders. However, limitations include reliance on two-dimensional periapical radiographs, which may underestimate periapical pathology compared with CBCT, and a single follow-up assessment, which may limit evaluation of long-term outcomes. The loss of 19 participants may have introduced selection bias, and operator-level effects could not be adequately analyzed due to data limitations, restricting assessment of clinician-related variability [11].

Conclusion and recommendation

Endodontic treatment at Jimma Medical Center demonstrated a high overall success rate, with favorable clinical, radiographic, and patient-reported outcomes, despite resource-related limitations in endodontic materials, equipment, and clinical infrastructure. Male gender, preoperative periapical pathology, primary irrigant type, and quality of coronal restoration were identified as independent determinants of treatment success, highlighting that both biological conditions and modifiable procedural factors—particularly effective intracanal disinfection and sound coronal sealing—play a key role in treatment outcomes in this resource-limited setting. Routine use of sodium hypochlorite (NaOCl) as the primary irrigant and improved emphasis on high-quality definitive coronal restorations, including cuspal coverage when indicated, are recommended to enhance success rates. At the system level, strengthening supply chains for essential endodontic materials and implementing standardized clinical protocols are essential. Future research should incorporate CBCT imaging, multicenter and longer follow-up designs, microbiological assessments of persistent infection, and evaluation of operator-related factors to further improve evidence and clinical practice.

Abbreviations

JMC

Jimma Medical Center

WHO

World Health Organization

Niti

Nickel Titanium

CBCT

Cone Beam Computed Tomography

ESE

European Society of Endodontology

PAI

Periapical Index

RCT

Root canal Treatment

NAOCL

Sodium Hypochlorite

EDTA

Ethylenediaminetetraacetic Acid

H₂O₂

Hydrogen peroxide

Authors’ contributions

KD, BT, and DG contributed equally to the conceptualization, data collection, and writing of the manuscript. DG led and KD conducted the development of the methodology and the data analysis. All authors reviewed and approved the final version of the manuscript and agreed that DG would serve as the corresponding author.

Funding

This study was funded by a Data Collection and Analysis Grant from Jimma University. The funder had no role manuscript preparation, or publication.

Data availability

The datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request (kdsagawakaf@gmail.com).

Declarations

Ethics approval and consent to participate

Ethical approval for this study was obtained from the Institutional Review Board of Jimma University, Institute of Health (Reference No. JUIH/IRB/344/25) prior to commencement of the study. Written informed consent was obtained from all participants before their inclusion in the study. Permission to review patient records was obtained from Jimma Medical Center. Participant confidentiality was maintained throughout the study by using unique identification codes and anonymized data. Participants were informed of their right to withdraw from the study at any time without any consequences for their current or future medical care. All procedures involving human participants were performed in accordance with the ethical standards of the Institutional Review Board of Jimma University and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.