Comparative Evaluation of Replantation Outcomes of Avulsed Teeth—Influence of Extraoral Time and Storage Medium: A CBCT-based Study

Abstract

Background

Tooth avulsion is a severe dental trauma predominantly affecting children and adolescents. Prognosis depends largely on extraoral time and storage medium before replantation. Cone-beam computed tomography (CBCT) provides superior evaluation of healing outcomes compared to traditional radiography.

Aim

To evaluate the influence of extraoral time and storage medium on clinical and radiographic outcomes of replanted permanent maxillary central incisors in children aged 9–14 years.

Materials and methods

This randomized, controlled, parallel-arm trial was conducted at a private dental college in India over 12 months, from July 2024 to July 2025. A total of 48 avulsed permanent maxillary central incisors from children aged 9 to 14 years were included based on standardized inclusion criteria and grouped according to extraoral dry time and storage medium. Clinical parameters (pain, pocket depth) and radiographic outcomes [lesion diameter (LD), apical diameter (AD), root wall thickness, and tooth–bone resorption] were evaluated at baseline, 6, and 12 months using CBCT and clinical examination. Data were analyzed with repeated measures ANOVA, correlation, and multiple linear regression, with p < 0.05 considered statistically significant.

Results

Significant improvements were observed in pain (p < 0.001), pocket depth (p < 0.001), lesion diameter (p < 0.001), and tooth–bone resorption (p < 0.001) over time. Tooth–bone resorption was the most protocol-sensitive parameter, with better protocols showing lower resorption scores. Larger lesion diameter and thinner root walls were significantly associated with increased resorption.

Conclusion

Rapid replantation with biologically compatible storage media and adjunctive root-surface treatments optimizes healing outcomes for avulsed teeth. CBCT is an indispensable tool for monitoring healing and guiding prognosis.

Introduction

Tooth avulsion, characterized by the complete displacement of a tooth from its alveolar socket, is a severe form of dental trauma commonly affecting children and adolescents. This condition is frequently associated with falls, contact sports, road traffic accidents, and physical altercations, especially during unsupervised play or peer conflicts. Rajan et al. reported a 58.6% prevalence of tooth avulsion among adolescents, with a strong association to aggressive behavior, inadequate parental knowledge, and delayed interventions, all of which compromise treatment outcomes.¹

Avulsion is considered a dental emergency, and its prognosis is critically dependent on timely and appropriate intervention. Among various influencing factors, the extraoral dry time—the duration for which the avulsed tooth remains outside the socket without preservation—plays a pivotal role in determining the viability of PDL cells. According to the International Association of Dental Traumatology (IADT), replantation within 15–20 minutes offers the most favorable prognosis due to better preservation of PDL cell viability.² Conversely, if the tooth remains dry for over 60 minutes, the risk of irreversible damage to the PDL sharply increases, often resulting in complications such as inflammatory root resorption and ankylosis.^3,4

Efforts to mitigate these adverse outcomes have focused on identifying effective interim storage media capable of maintaining cell viability. Hank's balanced salt solution (HBSS) remains the gold standard due to its physiological compatibility, supporting cellular survival for up to 12 hours.⁵ Milk, although more readily available, is less effective beyond 3–6 hours, while saliva and water have been associated with poor outcomes due to microbial contamination and unsuitable osmolarity.^6,7

Historically, outcome assessment in avulsed teeth has relied on conventional two-dimensional radiography. However, this method often lacks the sensitivity needed to detect subtle resorptive defects and periapical pathology. The advent of cone-beam computed tomography (CBCT) has transformed dental imaging by offering three-dimensional (3D) visualization of root surface changes, periapical healing, and bone remodeling with significantly higher diagnostic accuracy.⁸ CBCT enables clinicians to detect early signs of replacement or inflammatory resorption that might otherwise go unnoticed.

Despite the broad recognition of extraoral time and storage conditions as crucial prognostic factors, few studies have systematically correlated these variables with long-term healing outcomes using CBCT. For example, Malhotra et al. utilized CBCT to observe calcific metamorphosis but did not relate findings to storage media, while Bastos et al. examined resorption patterns postreplantation without evaluating the impact of procedural delays.^9,10 This highlights a significant gap in the literature regarding a comprehensive radiographic evaluation that integrates clinical variables and healing dynamics.

This study aims to fill that gap by conducting a CBCT-based comparative evaluation of replanted avulsed teeth, focusing specifically on the influence of extraoral time and storage media on clinical and radiographic outcomes. By correlating these variables with healing patterns, the findings are expected to enhance prognostic accuracy, guide clinical protocols, and ultimately improve the long-term success of avulsion management in pediatric and adolescent populations.

Materials and Methods

Study Design and Setting

This study was designed as a randomized, controlled, parallel-arm clinical trial conducted over a 12-month period (July 2024 to July 2025) in the Department of Pediatric and Preventive Dentistry, Saveetha Dental College and Hospital, SIMATS University, Chennai, India. Ethical approval was obtained from the Institutional Human Ethical Committee (Approval No.: IHEC/SDC/DT/PEDO-2204/24/232) and the Scientific Review Board. The trial was prospectively registered with the Clinical Trials Registry–India (CTRI/2024/12/077738). Written informed consent was obtained from all participants or their legal guardians prior to enrollment. A total of 48 avulsed permanent maxillary central incisors from children aged 9–14 years were included based on predefined eligibility criteria.

Inclusion Criteria

• Children who presented with avulsed permanent maxillary central incisors (tooth numbers 11 or 21) requiring emergency replantation, where the avulsed tooth had been stored in water, saline, or milk before replantation, or brought dry.

• Cases in which extraoral root canal treatment was deemed necessary and completed before replantation.

• Written informed consent was obtained from parents or legal guardians, with agreement to participate in scheduled CBCT-based periapical assessments.

• Willingness and ability of both child and parent/guardian to adhere to the 12-month follow-up schedule.

• Only cases involving maxillary central incisors were included in the final analysis, regardless of whether other teeth were replanted simultaneously.

Exclusion Criteria

• Children with systemic conditions or undergoing pharmacological treatments known to impair healing (e.g., diabetes mellitus, immunosuppressive therapy).

• Refusal by parents or guardians to consent to CBCT imaging or follow-up assessments.

• Cases with extensive orofacial trauma that could compromise replantation accuracy or radiographic interpretation.

• Loss to follow-up or noncompliance with the scheduled reviews.

• CBCT scans with significant artifacts or poor image quality prevent diagnostic evaluation.

Grouping Protocol

Cases were classified into four protocols according to extraoral dry time and the type of storage medium before replantation:

1. Protocol A: Extraoral dry time ≤12–18 hours, stored in commonly available media such as milk or other medium.

2. Protocol B: Extraoral dry time >18 hours, stored in milk or other medium, or teeth brought dry (irrespective of dry time).

3. Protocol C: Extraoral dry time ≤6–12 hours, stored in milk or other medium.

4. Protocol D: Extraoral dry time <6 hours, stored in milk or other medium.

Tooth Replantation Technique

In accordance with the inclusion criteria, all teeth underwent extraoral endodontic treatment before replantation. Teeth with closed apices received conventional root canal therapy, whereas those with open apices were treated with a 3 mm apical plug of mineral trioxide aggregate (MTA) followed by obturation with gutta–percha and sealer. Access cavities were sealed with glass ionomer cement before replantation.

Upon presentation, regardless of their prior storage medium, all avulsed teeth were placed in HBSS for 20 minutes to prevent further desiccation. This was followed by immersion in 5% doxycycline solution for 10 minutes to reduce bacterial contamination and promote PDL healing. Subsequent management varied by protocol:

• Protocol A: No additional root surface treatment beyond doxycycline; teeth were immersed in 0.4% stannous fluoride for 5 minutes to enhance mineralization and reduce inflammatory resorption risk (Fig. 1).

• Protocol B: Given the prolonged extraoral time and presumed loss of PDL vitality, root surfaces were treated with 1% citric acid for 5 minutes to remove necrotic tissue and promote connective tissue reattachment, followed by stannous fluoride conditioning (Fig. 2).

• Protocol C: Standard HBSS and doxycycline conditioning followed by stannous fluoride; citric acid was not used due to shorter extraoral duration (Fig. 3).

• Protocol D: Managed under ideal conditions with HBSS, doxycycline, and stannous fluoride treatment; citric acid was not used (Fig. 4).

Figs 1A to K.

Protocol A: (A) Extraoral photograph of the patient showing the avulsion site; (B) Photograph of the avulsed tooth in dry or wet condition; (C) Photograph of the tooth immersed in milk or HBSS (Hank's Balanced Salt Solution); (D) Clinical image of tooth immersion in HBSS, doxycycline, or fluoride; (E) Clinical image showing the tooth being reinserted into the socket for replantation; (F) Intraoral image showing a semirigid splint using wire and composite; (G) Image of repositioned and splinted tooth post-replantation; (H) Sagittal CBCT sections showing periodontal space and root morphology at baseline; (I) Follow-up radiographs/CBCT to assess healing and early signs of root resorption; (J) Mid-term assessment with CBCT at 6 months after treatment; (K) Final evaluation by CBCT at 12 months post-treatment

Figs 2A to K.

Protocol B: (A) Initial trauma showing soft tissue injury; (B) Storage medium condition and root surface appearance of the avulsed tooth; (C) Medium used to store the tooth; (D) Documentation of decontamination and conditioning of the tooth; (E) Confirmation of the replantation method used; (F) Documentation of tooth stabilization method post-replantation; (G) Immediate clinical outcome after replantation; (H) CBCT assessment of root integrity and socket condition; (I) Evaluation of treatment success or complications via CBCT; (J) Monitoring of healing, root development, and any resorption at 6 months; (K) Final outcome assessment including ankylosis or resorption at 12 months

Figs 3A to K.

Protocol C: (A) Clinical photograph at presentation before replantation; (B) Image before any clinical intervention on the avulsed tooth; (C) Tooth immediately after presentation; (D) Image during the clinical procedure for replantation; (E) Photograph during the replantation procedure; (F) Postreplantation image showing tooth stabilization; (G) Clinical image after the replantation procedure; (H) CBCT baseline image immediately postoperation; (I) Follow-up CBCT image at 3 months postreplantation; (J) Six-month follow-up CBCT image; (K) Twelve-month follow-up CBCT image to assess long-term outcome

Figs 4A to K.

Protocol D: (A) Clinical photograph at presentation before replantation; (B) Image before clinical intervention with the tooth stored in milk; (C) Milk medium used for tooth storage; (D) Image during the clinical procedure for replantation; (E) Photograph during the replantation procedure; (F) Post-replantation image showing tooth stabilization; (G) Clinical image after the replantation procedure; (H) CBCT baseline image immediately postoperation; (I) Follow-up CBCT image at 3 months post-replantation; (J) 6-month follow-up CBCT image; (K) 12-month follow-up CBCT image to assess long-term outcome

Before replantation in all protocols, the alveolar socket was irrigated with povidone–iodine and sterile saline. Clots were removed, and fresh bleeding was induced using mosquito forceps to facilitate revascularization. The tooth was then gently reinserted and stabilized using a semirigid splint of 0.4 mm braided ligature wire and composite resin extending to the adjacent teeth, which was maintained for 4 weeks. Occlusal adjustment was performed to ensure the replanted tooth remained out of occlusion.

Sample Size Calculation

An a priori power analysis in G*Power (ANCOVA, fixed effects) estimated that n = 41 would provide 95% power (α = 0.05) to detect a large effect (f = 0.90, ηp² ≈ 0.45) with four groups and eight covariates. To account for attrition, N = 48 was recruited. After exclusions and missed follow-ups, 36 participants (9 per group) were analyzed. A post hoc analysis showed that this final sample retained 90% power, confirming adequacy despite attrition.

A total of 48 participants were screened for eligibility, of whom four were excluded (three not meeting the inclusion criteria and one declining participation). The remaining 44 participants were randomized equally into four intervention groups (n = 11 each). All participants received the allocated interventions. During follow-up, six participants were lost due to nonreporting. In the final analysis, 9 participants per group were included, with minor exclusions across groups (Fig. 5).

Fig. 5.

CONSORT flow diagram of participant recruitment, allocation, follow-up, and analysis

Statistical Analysis

All analyses were performed using SPSS v26.0 (IBM Corp., Armonk, NY, USA). Continuous data were summarized as mean ± SD, and categorical data as frequencies/percentages. Repeated measures ANOVA assessed within-group changes over time, with Greenhouse–Geisser correction applied if sphericity was violated. One-way ANOVA with Bonferroni post hoc tests compared protocols across time points, and chi-square tests analyzed categorical outcomes. Associations between clinical and radiographic variables were tested with Pearson's correlation. Predictors of bone resorption at 12 months were explored using linear regression models, with results expressed as unstandardized (B) and standardized (β) coefficients, 95% confidence intervals (CI), R² and adjusted R² values, and overall model significance determined by the F-statistic. A final multivariate model was derived using a backward stepwise approach, with p < 0.05 as the threshold for significance.

Results

The present CBCT-based prospective study evaluated the impact of extraoral time and storage medium on the clinical and radiographic outcomes of replanted maxillary central incisors in children aged 9–14 years. Over a 12-month follow-up, significant improvements were observed in pain perception, periodontal pocket depth, lesion diameter (LD), apical diameter (AD), and bone healing, demonstrating the effectiveness of standardized replantation protocols. Among the variables measured, tooth–bone resorption (TBR) at 12 months was the most sensitive to protocol variations, showing significant differences between groups and highlighting its value as a prognostic marker in trauma-related healing. The study included 28 replanted permanent maxillary central incisors evaluated at baseline (T1), 6 months (T2), and 12 months (T3). The use of CBCT in the current study was instrumental in enhancing diagnostic accuracy, allowing for precise assessment of root resorption, periapical lesions, cortical bone changes, LD, AD, and RWL.

At T1, all protocols showed no pocket depth or resorption, with comparable apical and lesion diameters. By T2, there was a moderate increase in pocket depth (1.7–2.4 mm) and mild resorption (TBR ≈ 1.1–1.7), while lesion diameter values decreased across groups. At T3, clear differences emerged: protocols A and B showed greater disease progression, with deeper pockets (4.1–5.0 mm), higher resorption scores (2.07–2.66), and in protocol B, a pronounced apical widening (2.03 mm). Protocol C maintained more favorable outcomes, with minimal resorption (0.17), shallower pocket depth (1.7 mm), and the smallest lesion diameter (0.26 mm). Protocol D showed intermediate results, with modest pocket depth and resorption but a narrower apical diameter (0.51 mm). Overall, protocols A and B reflected the most deterioration, while protocol C displayed the most favorable healing pattern, as shown in Table 1. At T2, protocol-related differences were significant for pocket depth (p = 0.024), TBR (p < 0.001), AD (p < 0.001), and LD (p < 0.001). At T3, TBR remained protocol-sensitive, with lower values in cases having shorter extraoral times and biologically favorable storage media.

Table 1.

Protocol-wise mean ± SD of pocket depth, TBR, AD, and LD at T1 (baseline), T2, and T3, comparing outcomes across extraoral time and storage medium groups

Variable	Time	Protocol A	Protocol B	Protocol C	Protocol D
Pocket depth (mm)	T1	0.00 ± 0.00	0.00 ± 0.00	0.00 ± 0.00	0.00 ± 0.00
	T2	1.71 ± 0.76	2.29 ± 1.38	2.29 ± 1.25	2.43 ± 1.39
	T3	4.14 ± 1.86	5.00 ± 1.53	1.71 ± 0.76	2.29 ± 1.38
TBR (Tooth–bone resorption)	T1	0.00 ± 0.00	0.00 ± 0.00	0.00 ± 0.00	0.00 ± 0.00
	T2	1.07 ± 0.18	1.66 ± 0.28	1.14 ± 0.38	1.07 ± 0.18
	T3	2.07 ± 0.23	2.66 ± 0.17	0.17 ± 0.08	1.03 ± 0.18
AD (Apical diameter, mm)	T1	1.01 ± 0.26	0.96 ± 0.23	1.00 ± 0.27	0.99 ± 0.22
	T2	1.05 ± 0.28	1.09 ± 0.32	1.09 ± 0.34	1.04 ± 0.26
	T3	0.97 ± 0.21	2.03 ± 0.11	0.97 ± 0.21	0.51 ± 0.07
LD (Lesion diameter, mm)	T1	0.86 ± 0.14	0.85 ± 0.11	0.91 ± 0.12	0.87 ± 0.15
	T2	0.50 ± 0.27	0.42 ± 0.25	0.42 ± 0.26	0.40 ± 0.24
	T3	0.87 ± 0.13	0.44 ± 0.26	0.26 ± 0.10	0.44 ± 0.26

Repeated-measures ANOVA revealed significant temporal improvements across most clinical and radiographic parameters, with consistent trends observed across all protocols. Mauchly's test confirmed the assumption of sphericity (W =0.940, χ² = 1.60, p = 0.450; Greenhouse–Geisser ε = 0.944). Pain scores (VAS) showed a marked decline from 8.00 ± 0.77 at baseline (T1) to 0 at both 6 months (T2) and 12 months (T3) across all protocols (p < 0.001). Pocket depth and TBR also decreased significantly from T1 to T2 and T3 across all groups (p < 0.001), though the additional reduction from T2 to T3 for pocket depth was only marginally significant (p ≈ 0.050). LD demonstrated progressive reductions at each interval (p < 0.001), while AD remained relatively stable, with no significant temporal change noted in any protocol (p = 0.168). Taken together, these findings indicate that all protocols were effective in producing substantial clinical and radiographic healing within the first 6 months, with outcomes largely maintained at 12 months (Table 2).

Table 2.

Mean, standard deviation (SD), and 95% confidence intervals (CI) for continuous clinical and radiographic parameters at baseline (T1), 6 months (T2), and 12 months (T3) across all protocols. p-values were obtained using repeated-measures ANOVA to assess temporal changes within protocols. p < 0.05 is statistically significant

Parameter	Protocol	T1 (Mean ± SD, 95% CI)	T2 (Mean ± SD, 95% CI)	T3 (Mean ± SD, 95% CI)	p-value (RM-ANOVA)
VAS	1	8.00 ± 0.82 (7.24–8.76)	0.00 ± 0.00 (−)	0.00 ± 0.00 (−)	< 0.001*
	2	8.00 ± 0.82 (7.24–8.76)	0.00 ± 0.00 (−)	0.00 ± 0.00 (−)
	3	8.00 ± 0.82 (7.24–8.76)	0.00 ± 0.00 (−)	0.00 ± 0.00 (−)
	4	8.00 ± 0.82 (7.24–8.76)	0.00 ± 0.00 (−)	0.00 ± 0.00 (−)
Pocket depth	1	0.00 ± 0.00 (−)	3.29 ± 1.60 (1.80–4.77)	4.14 ± 1.86 (2.42–5.87)	< 0.001*
	2	0.00 ± 0.00 (−)	1.86 ± 0.69 (1.22–2.50)	5.00 ± 1.53 (3.59–6.41)
	3	0.00 ± 0.00 (−)	1.86 ± 0.69 (1.22–2.50)	1.71 ± 0.76 (1.02–2.41)
	4	0.00 ± 0.00 (−)	1.71 ± 0.76 (1.02–2.41)	2.29 ± 1.38 (1.01–3.56)
TBR	1	0.00 ± 0.00 (−)	1.30 ± 0.14 (1.17–1.43)	2.07 ± 0.23 (1.86–2.28)	< 0.001*
	2	0.00 ± 0.00 (−)	1.66 ± 0.24 (1.44–1.88)	2.66 ± 0.17 (2.50–2.82)
	3	0.00 ± 0.00 (−)	0.79 ± 0.14 (0.66–0.91)	0.17 ± 0.08 (0.10–0.24)
	4	0.00 ± 0.00 (−)	1.19 ± 0.14 (1.06–1.31)	1.03 ± 0.18 (0.86–1.19)
AD (apical diameter)	1	0.93 ± 0.23 (0.72–1.14)	0.97 ± 0.21 (0.78–1.16)	0.97 ± 0.21 (0.78–1.16)	0.168
	2	1.20 ± 0.22 (1.00–1.40)	1.56 ± 0.15 (1.42–1.70)	2.03 ± 0.11 (1.93–2.13)
	3	0.93 ± 0.23 (0.72–1.14)	0.97 ± 0.21 (0.78–1.16)	0.97 ± 0.21 (0.78–1.16)
	4	0.90 ± 0.18 (0.73–1.07)	0.79 ± 0.11 (0.69–0.88)	0.51 ± 0.07 (0.45–0.58)
Lamina dura	1	0.86 ± 0.22 (0.66–1.06)	1.29 ± 0.14 (1.16–1.41)	−	< 0.001*
	2	0.86 ± 0.22 (0.66–1.06)	1.20 ± 0.16 (1.05–1.35)	−
	3	0.94 ± 0.15 (0.80–1.08)	0.64 ± 0.13 (0.53–0.76)	−
	4	0.86 ± 0.22 (0.66–1.06)	1.20 ± 0.16 (1.05–1.35)	−

QUALITY, Quality of life; significant correlations were observed except for LD ↔ RWL (p > 0.05),* denote levels of statistical significance

Correlation analysis at T3 revealed several significant associations between clinical and radiographic outcomes. Pocket depth showed a strong positive correlation with tooth–bone resorption (r = 0.631, p < 0.001) and quality of life scores (r = 0.640, p < 0.001), and a moderate correlation with lesion diameter (r = 0.438, p = 0.020). Tooth–bone resorption was strongly negatively correlated with root wall thickening (r =−0.742, p < 0.001), while also demonstrating a robust positive association with quality of life (r = 0.813, p < 0.001). Lesion diameter showed a weak, nonsignificant negative correlation with root wall thickening (r =−0.296, p = 0.126). At 12 months, TBR correlated positively with LD and AD, and negatively with RWL. Quality of life tended to improve with favorable clinical and radiographic parameters (Table 3).

Table 3.

Pearson's correlation coefficients at T3 between pocket depth

Variable pair	R	p-value	Direction
Pocket depth ↔ TBR	0.631	< 0.001	Positive, strong
Pocket depth ↔ LD	0.438	0.02	Positive, moderate
TBR ↔ RWL	−0.742	< 0.001	Negative, strong
TBR ↔ QUALITY	0.813	< 0.001	Positive, very strong
Pocket depth ↔ QUALITY	0.64	< 0.001	Positive, strong
LD ↔ RWL	−0.296	0.126 (NS)	Negative, weak

Figure 6 highlights that most variables demonstrated weak to moderate associations, with both positive and negative trends observed. Pocket depth at later time intervals showed positive correlations with TBR and AD, indicating that as pocket depth increased, there was a tendency for these parameters to rise as well. In contrast, LD showed weaker and in some cases negative associations, suggesting limited dependence on changes in pocket depth. The significance markers reveal that only a few of these correlations reached statistical significance, while many remained nonsignificant, reflecting the variability within groups and the small number of protocols. Overall, the analysis suggests that while certain parameters may shift together, the strength of linear relationships across variables is limited, underscoring the multifactorial nature of these clinical outcomes.

Fig. 6.

Correlation heatmap based on protocol-wise means (red indicates positive correlations, blue indicates negative correlations, and stars (*,**,***) denote levels of statistical significance)

At T3, internal/external resorption (χ² = 13.067, p = 0.004), bone loss (χ² = 20.813, p < 0.001), failure criteria (χ² = 34.954, p < 0.001), root wall thickening (χ² = 28.779, p < 0.001), lamina dura integrity (χ² = 17.5, p = 0.001), and quality of life (χ² = 32.343, p < 0.001) all showed significant differences between protocols. At T2, failure criteria (χ² = 22.167, p < 0.001) and quality of life (χ² = 16.8, p = 0.001) were also significant, while lamina dura integrity showed a near-significant trend (χ² = 6.574, p = 0.087). In contrast, mobility and tenderness on percussion did not differ significantly across protocols (p > 0.05) (Table 4).

Table 4.

Chi-square analysis of categorical outcomes showed significant protocol-related variations in several categorical parameters

Parameter	Time	Mean ± SD	χ²	p-value
TR	T1	8.00 ± 0.77	2.154	0.541
	T2	0.00 ± 0.00	2.8	0.423
	T3	0.00 ± 0.00	13.067	0.004*
Mobility	T1	0.00 ± 0.00	—	—
	T2	1.86 ± 0.59	—	—
	T3	3.29 ± 1.92	3.111	0.375
BL	T1	0.00 ± 0.00	—	—
	T2	1.23 ± 0.35	7.636	0.054
	T3	1.48 ± 0.99	20.813	<0.001*
FAILCRIT	T1	0.00 ± 0.00	—	—
	T2	0.99 ± 0.24	22.167	<0.001*
	T3	1.07 ± 0.34	34.954	<0.001*
RWT	T1	0.00 ± 0.00	—	—
	T2	1.12 ± 0.59	—	—
	T3	0.88 ± 0.19	28.779	<0.001*
TOP	T1	0.00 ± 0.00	—	—
	T2	1.08 ± 0.30	—	—
	T3	0.50 ± 0.30	—	—
Integrity LD	T1	0.00 ± 0.00	—	—
	T2	—	6.574	0.087
	T3	—	17.5	0.001*
Quality	T1	0.00 ± 0.00	—	—
	T2	—	16.8	0.001*
	T3	—	32.343	<0.001*

TR, internal/external resorption; BL, bone loss; FAILCRIT, failure criteria; TOP, tender on percussion; QUALITY, quality of life; *significant associations observed primarily at T3

Most variables in the regression analysis in Figure 7 were nearly constant, producing flat regression lines and perfect or negligible R² values. Pocket depth showed no predictive value for changes in AD or lamina dura, and TBR remained independent of pocket depth with an R² of 1.0 due to a lack of variation. The regression heatmap confirmed that only a few pairs had measurable relationships; most correlations were weak or absent. These results suggest that Pocket Depth, TBR, AD, and LD are not linearly related and are likely affected by other factors outside this dataset.

Fig. 7.

Regression heatmap depicting associations between pocket depth (independent variable at T1, T2, and T3) and outcome variables (VAS, TBR, AD, LD); color intensity indicates the strength of the relationship (R²), with darker shades reflecting stronger correlations

Multiple linear regression analysis was conducted with TBR at 12 months as the dependent variable, as shown in Table 5. The model was statistically significant (p < 0.001) and explained 78.4% of the variance (adjusted R² = 0.784). Among the predictors, protocol quality was highly influential, with better protocols—defined by shorter extraoral times and ideal storage conditions—significantly associated with lower levels of total bone resorption at 12 months (β = −0.412, p = 0.002). In contrast, a larger lesion diameter at 12 months predicted higher total bone resorption (β = 0.356, p = 0.009), while a thicker root wall at 12 months was associated with reduced resorption (β = −0.298, p = 0.015). After adjustment, apical diameter and pocket depth were not found to be significant predictors of total bone resorption.

Table 5.

Multiple linear regression analysis showing the association between selected clinical and radiographic predictors at 12 months (T3) and the dependent variable

Predictor	B (Unstd.)	SE	β (Std.)	t	p-value	95% CI for B
LD_T3	0.613	0.356	0.186	1.724	0.1	(−0.125, 1.351)
MOBILITY_T3	−0.026	0.21	−0.013	−0.124	0.903	(−0.461, 0.410)
BL_T3	0.328	0.244	0.331	1.344	0.194	(−0.177, 0.833)
FAILCRIT_T3	0.471	0.331	0.437	1.424	0.17	(−0.214, 1.155)
RWL_T3	0.373	0.254	0.249	1.468	0.158	(−0.148, 0.894)
Integrity LD_T3	−0.822	0.337	−0.42	−2.441	0.024	(−1.515, −0.129)
QUALITY_T3	−0.034	0.246	−0.024	−0.14	0.89	(−0.543, 0.476)

B, unstandardized coefficient; SE, standard error; β, standardized coefficient; t,t-statistic; 95% CI, 95% confidence interval for B. Statistical significance was set at p < 0.05

Discussion

Conventional radiography has long been the primary diagnostic aid for assessing traumatic dental injuries. However, its limitations are well established, as it provides only a 2D representation of 3D structures. This inherently restricts visualization and often results in the superimposition of anatomical details, masking early or subtle pathological changes. Taravati et al.¹¹ highlighted that although widely used, periapical radiographs are not reliable for detecting incipient resorptive lesions, necessitating the incorporation of advanced imaging modalities for more accurate assessment.

Avulsion is one of the most severe dental injuries in pediatric patients, with long-term outcomes being profoundly influenced by extra-alveolar time, the type of storage medium employed, and the adjunctive procedures performed before replantation. As early as 1981, Blomlöf⁶ identified the crucial role of storage media, noting that milk and saliva could help preserve PDL viability better than dry conditions. Pérez et al.⁵ subsequently confirmed that inappropriate storage, even for as short as 30 minutes, can lead to significant PDL necrosis and trigger severe inflammatory root resorption. Trope³ further emphasized the importance of rapid replantation and biologically compatible media, describing these as the most significant prognostic factors for replanted teeth.

The clinical management of avulsed teeth has evolved significantly over time. Panzarini et al.¹² conducted an extensive review on root surface treatments in delayed replantation, emphasizing the use of fluoride, citric acid, and other conditioning agents to enhance periodontal reattachment. These findings align with the guidelines proposed by Andersson et al.,⁴ who updated the IADT recommendations in 2012, underscoring the need for immediate replantation, appropriate storage, and adjunctive procedures to optimize outcomes. The clinical importance of using compatible storage solutions was further strengthened by the work of Sigalas et al.,¹³ who demonstrated that HBSS could maintain PDL cell metabolism for extended durations, outperforming other commonly used media. In parallel, Hwang et al.⁷ reported similar benefits of biological storage solutions, reinforcing the superiority of HBSS in preserving cellular viability.

The value of CBCT in dental traumatology has been widely recognized. Patel et al.¹⁴ in 2007 highlighted its superiority over conventional radiography for evaluating periapical pathology and subtle root surface changes. Levin et al. and later Bastos et al. also supported this view, showing that CBCT could detect early external resorption, fractures, and periapical lesions more effectively than traditional radiographs. More recently, Patel and Saberi¹⁵ reiterated these benefits, demonstrating that CBCT offers an unparalleled 3D view, making it indispensable in trauma management and follow-up assessments.

Our study findings showed that protocols with shorter extra-alveolar durations, particularly Protocol D, where replantation occurred within 6 hours, and HBSS was used as the storage medium, resulted in more favorable healing outcomes. These results echo the earlier work of Sigalas et al.¹³ and Hwang et al.⁷, where HBSS demonstrated a superior ability to sustain cellular viability. Conversely, storage in dry conditions has consistently shown detrimental effects, with increased risk of inflammatory resorption and ankylosis. These biological processes are driven by necrotic PDL remnants, which serve as stimuli for osteoclastic activity and cytokine release, leading to extensive root resorption. Andreasen et al. and Khinda et al.^4,16 stressed that necrotic remnants are major triggers for resorption, an observation strongly reinforced in the present study.

Pain perception in this trial, evaluated through the visual analog scale (VAS), declined significantly from baseline through 6 and 12-months. This reduction in pain is attributable to effective infection control and disinfection achieved through extraoral root canal treatment. Trope³ advocated immediate endodontic therapy for avulsed teeth to minimize bacterial colonization, a recommendation further supported by Krastl et al.¹⁷. The latter authors, along with Jain et al.,¹⁸ documented that early disinfection and obturation substantially reduce postoperative discomfort and inflammatory sequelae, aligning with our findings of reduced pain scores and enhanced patient comfort during follow-up.

Another important aspect highlighted in this study is the role of lesion diameter and root wall thickness as predictors of resorption. Larger lesion diameters were positively correlated with higher resorption rates, which can be explained by the extensive inflammatory environment surrounding larger defects. Patel and Saberi¹⁵ previously demonstrated that larger periapical lesions strongly predict resorptive progression, supporting the biological rationale that inflammation drives osteoclastic activity. In contrast, greater root wall thickness showed a protective effect, limiting clastic cell penetration and reducing the risk of resorption. Malhotra and Mala had earlier emphasized that teeth with thinner dentinal walls are significantly more vulnerable to resorption and fracture, which resonates with our regression findings.

Periodontal pocket depth improved over time across all protocols but showed no significant inter-protocol variation. This suggests that once favorable replantation conditions are met, periodontal reattachment progresses similarly regardless of the storage medium. This observation is consistent with the findings of Mehta and Verma¹⁹, Tuna et al.,²⁰ and Venugopal,²¹ who concluded that adjunctive root surface treatments—such as fluoride, citric acid, and doxycycline—can reduce resorption and enhance healing by removing necrotic remnants and promoting mineralization. The consistency of adjunctive therapies in our trial likely minimized variability, explaining the absence of differences in periodontal depth across groups. Coste et al.²² also showed that surface treatments and splinting techniques are more influential in periodontal healing than storage media alone, a conclusion mirrored in our results.

Tooth–bone resorption, however, demonstrated clear inter-protocol differences, being most sensitive to extraoral duration and storage medium. Protocol D consistently yielded the lowest resorption scores, confirming the hypothesis that better protocols preserve PDL viability. The adjunctive use of semirigid splinting for 4 weeks in our study further contributed to these favorable results. Evans²³ cautioned against rigid splints beyond 2 weeks due to increased ankylosis risk, whereas Fouad et al.²⁴ and Prasada et al.²⁵ endorsed semirigid splints as the standard of care, promoting physiological mobility and reducing adverse outcomes. The lack of significant mobility or percussion sensitivity in our study supports this consensus.

The integration of CBCT was instrumental in our study, allowing precise measurement of lesion size and structural integrity, and establishing robust correlations between clinical protocols and radiographic outcomes. Similar conclusions were drawn by Patel et al.,¹⁴ and Patel and Saberi,¹⁵ all of whom emphasized the superior diagnostic accuracy of CBCT in trauma-related cases. In particular, CBCT enabled us to demonstrate that reductions in lesion diameter and increases in root wall thickness were strongly associated with decreased resorption, thereby reinforcing the biological plausibility of these parameters.

While our results are promising, it is essential to acknowledge the limitations. A 12-month follow-up may be insufficient to capture late complications such as ankylosis or replacement resorption, which often present years after injury. Coste et al.²² highlighted that long-term follow-up is crucial for detecting such complications. Moreover, variables such as trauma severity, patient compliance, and operator technique may have introduced confounding factors. Future research must therefore include larger, multicenter cohorts with extended follow-up to validate these findings.

The future scope of this research lies in exploring novel biomaterials, advanced imaging modalities, and regenerative approaches to further improve replantation outcomes. Sharma et al.²⁶ emphasized the potential of platelet-rich fibrin (PRF) in trauma management, while Bakhtiar et al.²⁷ and Martens et al.²⁸ reported encouraging results with stem cell-based scaffolds for enhancing regenerative endodontics. Huang et al.²⁹ underscored the importance of cell-based regenerative strategies in improving long-term prognosis. Furthermore, the emergence of artificial intelligence in dental radiology and endodontics, as highlighted by Alraisi et al.³⁰ and He et al.³¹, promises to revolutionize early detection, monitoring, and prediction of trauma-related complications, paving the way for personalized and precision-based management strategies.

Finally, recent contributions by Piriyanga et al.,³² Sathish et al.,³³ and Doshi and Ranjan³⁴ expand the evidence base for novel biomaterials, digital scanning accuracy, and evolving endodontic practice trends, which collectively reflect the direction of contemporary pediatric dentistry toward innovation and precision. Similarly, newer clinical trials by Aarthi and Ravikumar^35,36 and Ravikumar et al.³⁷ highlight that, beyond clinical success, child-centered factors such as comfort, sensory acceptability, and treatment compliance are pivotal in long-term outcomes. These insights parallel our findings, where storage medium, extraoral time, and supportive protocols influenced not only biological healing but also the overall feasibility and acceptability of replantation in young patients.

Conclusion

In conclusion, this study demonstrates that while pain, periodontal pocket depth, lesion diameter, and apical morphology improve consistently across protocols, tooth–bone resorption remains the most sensitive indicator of protocol quality. The associations between larger lesion diameter and higher resorption, and between thicker root walls and lower resorption, can be explained by biological and structural factors. Larger lesions reflect greater tissue destruction and inflammatory activity, which promote osteoclastic resorption, whereas thicker dentinal walls offer structural resistance against clastic activity. Protocol quality further modifies these outcomes by minimizing tissue stress and preserving PDL viability, thereby reducing resorptive triggers. By integrating these findings with CBCT-based assessment, the present study highlight the importance of rapid replantation, biologically compatible storage media, and adjunctive treatment strategies in ensuring favorable long-term outcomes for avulsed teeth.

Acknowledgments

The authors sincerely thank the Department of Pediatric and Preventive Dentistry, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, India, for providing the facilities and support necessary to conduct this study. The authors are also grateful to all the children and their parents for their support throughout the study.

Author Contributions

Harsh Sanjaykumar Baldawa: Patient recruitment, data collection, clinical procedures, investigation, writing original draft preparation.

R Ramesh: Conceptualization, methodology, study design, supervision, clinical procedures, methodology, statistical analysis, interpretation of data, manuscript review and editing, visualization, and final approval of the manuscript.

AI Disclosure

Artificial intelligence (AI)-assisted technologies, including OpenAI ChatGPT (GPT-5.5), were used to assist in generating SPSS-based graphical visualizations (including correlation and regression heatmaps), language editing, grammar refinement, and preparation of figure descriptions. All statistical analyses were performed using SPSS by the authors, and all results, scientific interpretations, and conclusions were independently verified by the authors. The authors critically reviewed, edited, and take full responsibility for all AI-assisted content included in this manuscript.

Orcid

Harsh Sanjaykumar Baldawa https://orcid.org/0009-0009-2295-6875

R Ramesh https://orcid.org/0000-0002-1957-3867

Data Availability

All data supporting the findings of this study are presented within the manuscript in the form of tables, figures, and study results. No supplementary dataset is available.