Efficacy of Submucosal Polydeoxyribonucleotide Injection after Impacted Mandibular Third Molar Extraction: A Randomized Controlled Trial

Abstract

Purpose

This study aimed to evaluate the efficacy of polydeoxyribonucleotide (PDRN) injection after impacted mandibular third molar (IMTM) extraction. The primary outcome was postoperative pain, while secondary outcomes included postoperative swelling, periodontal pocket depth, and patient-reported outcome.

Materials and Methods

Thirty medically uncompromised patients who underwent bilateral extraction of IMTMs were enrolled in the clinical study. PDRN was randomly injected on the experimental side, while normal saline was injected on the control side. Postoperative pain was assessed using a visual analog scale. Postoperative swelling was evaluated via linear measurements based on the Laskin method. Furthermore, three-dimensional volumetric analysis was conducted by superimposing serial facial scans obtained at baseline (preoperatively) and on postoperative days 3 and 7. Pocket probing depth was evaluated using a periodontal probe. Patients’ postoperative morbidity and subjective perceptions were evaluated using the patient-centered outcome questionnaire. Statistical software was used to evaluate the data, and p<0.05 was considered statistically significant.

Results

Patients demonstrated statistically meaningful reductions in postoperative pain, swelling, and discomfort on the experimental side.

Conclusion

The results suggest that PDRN injection can be a suitable option to mitigate postoperative complications after IMTM extraction. However, further randomized controlled trials are required to confirm the reliability of the study and verify its suitability.

Graphical Abstract

INTRODUCTION

Impacted mandibular third molar (IMTM) extraction is one of the most commonly performed surgical procedures in oral surgery.¹ IMTMs are frequently associated with various pathological conditions, including pericoronitis, dental caries, odontogenic tumors, neurogenic pain, and periodontal defects adjacent to the second molar.² IMTM extraction typically necessitates mucoperiosteal flap elevation and osteotomy, which inevitably lead to soft tissue damage and alveolar bone resorption.³ Postoperative pain and swelling should be optimally managed and reduced to improve the patient’s quality of life (QOL). The recovery of periodontal tissues after IMTM surgery should also be considered. Accordingly, efforts are ongoing to identify therapeutic molecules that can alleviate postoperative inflammatory complications through local or systemic administration following IMTM surgery.⁴

Polydeoxyribonucleotides (PDRN), derived from the sperm of Oncorhynchus mykiss or Oncorhynchus keta, are low molecular weight DNA fragments known for their ability to 1) stimulate cell migration and growth, 2) promote extracellular matrix protein production, 3) reduce inflammation by suppressing pro-inflammatory cytokine secretion, and 4) enhance wound healing.⁵,⁶,⁷ Their beneficial effects, such as promoting cell migration, growth, and angiogenesis while attenuating inflammation, have been demonstrated in skin regeneration in both preclinical and clinical studies (1990–2016).⁸ As a regenerative agent, PDRN has been widely used in various medical fields, including diabetic foot ulcers, thermal injuries, rheumatoid arthritis, and skin cosmetics.⁹,¹⁰ However, the clinical application of PDRN in dentistry, especially in the oral surgery field, remains relatively unknown.¹⁰ Therefore, this clinical study is the first to evaluate the effect of submucosal PDRN injection (PI) after IMTM extraction. A prospective, randomized, split-mouth clinical trial was conducted in 30 medically uncompromised patients who had undergone bilateral extraction of IMTMs by a single surgeon.²,⁴ In the experimental group, PDRN was randomly injected on one side. In the control group, normal saline was injected on the opposite side. Postoperative pain was measured as a primary outcome to determine sample size requirements and statistical power. Postoperative swelling, pocket probing depth, and the patient-centered outcome questionnaire (PCOQ) were measured as secondary outcomes to evaluate the effect of submucosal PI.

MATERIALS AND METHODS

Study design and patients

An initial pilot study was conducted with 5 patients (10 IMTMs) to estimate the sample size for the clinical trial. Based on this pilot data, the null hypothesis was rejected with 80% statistical power at a significance level of 0.05.¹¹ Based on the mean visual analog scale (VAS) scores of the pilot study (PDRN 0.80±0.84 and placebo 1.80±1.92), a sample size of 30 patients was estimated.²,¹² To evaluate the effect of PI on postoperative variables, a prospective, randomized, double-blinded study was conducted from September 2024 to February 2025.¹,² Thirty patients without medical conditions that could influence the surgical procedure or postoperative wound healing were enrolled in the clinical study (Table 1).² In a split-mouth design involving 30 patients and 60 surgical sites, PDRN was administered to 16 left-sided and 14 right-sided sites, with normal saline injected contralaterally as the control. Patients with bilateral IMTMs of comparable surgical difficulty, as evaluated according to the Winter, Pell and Gregory classification, and with well-controlled systemic conditions were included. Exclusion criteria comprised autoimmune diseases, hemorrhagic disorders, and psychiatric disorders or suspected psychiatric conditions. Participants were also excluded based on the presence of known hypersensitivity to PDRN, pregnancy, a confirmed diagnosis of malignancy or ongoing chemotherapy, and a history of alcohol dependence. Additionally, any individual considered unsuitable for study participation based on the investigator’s discretion was excluded.⁴ The Institutional Review Board (IRB) of Wonju Severance Christian Hospital approved the study (IRB No. CR-124031). This study was registered with the Clinical Research Information Service (CRIS) of the Korea Disease Control and Prevention Agency (CRIS No. KCT0010231). All patients were referred to the Department of Oral and Maxillofacial Surgery and recommended for bilateral IMTM extraction. Written informed consent was obtained from all patients, who voluntarily agreed to undergo the procedure and declared their willingness to return at regular intervals for evaluation at 3, 7, 14, and 60 days after surgery.¹³,¹⁴,¹⁵

Table 1. Patient’s Demographic Characteristics (n=30).

Variable		Value
Race/ethnicity
	Asian (East Asian)	27 (90.0)
	Asian (Southeast Asian)	2 (6.7)
	Caucasian	1 (3.3)
Sex
	Male	23 (76.7)
	Female	7 (23.3)
Age (yr)		28.87±12.07

Data are presented as mean±standard deviation or n (%).

Blinding

Information regarding the type of injection administered at each extraction site was concealed from the patient, operator, evaluator (responsible for examinations and outcome measurements), and statistician. An external study collaborator, independent of the operator and evaluator, was responsible for allocating participants to the experimental and control groups and assigning the random sequence to ensure allocation concealment. Prior to surgical intervention, a sealed envelope containing a randomized list of PI sites was securely held by the external study collaborator, who had no further involvement in the clinical trial. The assigned interventions were prepared in identical syringes with the same packaging and appearance to maintain blinding. Data recording and statistical analysis were conducted using group codes “A” for PDRN and “B” for placebo, using Microsoft Excel (Microsoft, Redmond, WA, USA). The randomization code was not disclosed until completion of all clinical procedures and statistical analyses.¹¹

Surgical procedures and further management

All surgeries were performed by a single surgeon (K.H.J) on the same day under local anesthesia. All patients were radiologically screened with a panoramic X-ray and cone-beam computed tomography (CS 9600, Carestream Dental LLC. 3625 Cumberland Blvd. Ste. 700, Atlanta, GA, USA) to assess the anatomical relationship between the inferior alveolar nerve and both IMTMs.¹⁶,¹⁷,¹⁸ All surgeries were performed under strict aseptic conditions to prevent cross-contamination. Patients were informed that they would receive a PI on one side but were not informed of which side was allocated to PDRN. Consecutive IMTM surgeries were performed in order of random assignments.² All patients rinsed their mouths for 1 minute with a 0.2% chlorhexidine mouthwash before surgery. Bilateral inferior alveolar nerve block anesthesia and infiltration anesthesia (lidocaine HCl 2% injection Daihan, Daihan PharmCo. Ltd, Seoul, Korea) were administered at both surgical sites. Vertical and horizontal incisions were made on the buccal side of the mandibular second molar to carefully elevate the mucoperiosteal flap. Osteotomy was performed using a carbide fissure bur (SSW HP-702, SS White Dental, Lakewood, NJ, USA) and a low-speed straight handpiece (NSK EX-6, Nakanish Inc., Kanuma, Tochigi, Japan) at 200000 rpm under sufficient saline irrigation. To ensure the surgeon remained blinded to the allocation of the experimental and control sides, an external study collaborator prepared and provided the assigned injections. PDRN (Zerone Cellvane Korea, Seoul, Korea) injection was done on the experimental side. A total of 1.0 mL (1.875 mg of PDRN) was injected at the base of the mucoperiosteal flap, 0.5 mL at the mesial margin, and 0.5 mL at the distal margin.⁴,¹⁵ On the control side, a saline solution of 1.0 mL was administered as a placebo in the same manner. After the extraction of IMTMs, the elevated mucoperiosteal flap was repositioned, and simple interrupted sutures were applied. Every patient received oral medication including antibiotics (cefditoren pivoxil 100 mg three times daily) and an analgesic (aceclofenac 100 mg three times daily) for 5 days after IMTM surgery (Figs. 1 and 2). Patients were monitored throughout the follow-up period for clinical signs of inflammation, including erythema, swelling, pain, discoloration, and functional impairment. When systemic inflammation was suspected, C-reactive protein and interleukin-6 levels were evaluated. Fortunately, no instance of systemic inflammation was identified in any of the cases.¹⁹ To minimize the risk of cross-contamination, patients were instructed to maintain good oral hygiene throughout the clinical trial period. At each follow-up visit, atraumatic bilateral intraoral dressings were performed without disrupting the healing process, while maintaining the integrity of the blood clot.

Fig. 1. Preoperative panoramic X-ray.

Fig. 2. Intra-operative photos. (A) Experimental group (polydeoxyribonucleotide injection). (B) Control group (Normal Saline injection).

Postoperative examinations

Patients were selected according to the inclusion criteria, underwent general physical examination, filled out information sheets, signed the informed consent for PI, and received their randomization number. To minimize bias and maintain blinding, a surgeon who had not operated on patients conducted postoperative examinations, collected questionnaires, and reported all postoperative information to avoid underestimating complications. The primary outcome of the study was postoperative pain. The secondary outcomes included postoperative swelling, changes in pocket probing depth assessing periodontal tissue recovery 2 months after surgery, and PCOQ scores evaluating postoperative QOL. Postoperative pain and swelling were measured at postoperative day 3 (POD3), marking the peak of the acute inflammatory response.²⁰,²¹ Postoperative pain and swelling were measured on POD7, when the blood clot was progressively replaced by granulation tissue and inflammatory responses began to subside. On POD14, as granulation tissue underwent further maturation and woven bone formation began, pain duration and PCOQ were assessed.²¹ Finally, pocket probing depth was measured for long-term follow-up (POD60).

Pain

Pain during postoperative periods (POD3 and POD7) was evaluated using a VAS of 10 units in combination with a graphic rating scale ranging from 0 (absence of pain or discomfort) to 10 (maximum pain or discomfort).²,²² At 14 days after surgery, patients were questioned as to how many days their pain had persisted.

Postoperative swelling

Facial swelling was assessed using a tape measure and quantified as the sum of two linear measurements along defined reference points. The reference points included the tragus (T), oral commissure (O), lateral canthus of the eye (L), and gonion (G). The horizontal measure corresponded to the distance between the T and O. The vertical measure corresponded to the distance between the L and G²³ (Fig. 3).

Fig. 3. Reference points in linear measurement for facial swelling. (A) Tragus (T)-oral commissure (O). (B) Lateral canthus (L)-gonion (G). Facial swelling was calculated as a sum of two linear measurements.

The arithmetic sums of the two measurements determined the facial measurements. The percentage of facial swelling was calculated by subtracting the preoperative measurement from the postoperative measurement, dividing the difference by the preoperative value, and multiplying by 100. Changes in linear measurement from preOP to POD3 (ΔPOD3–preOP) and from preOP to POD7 (ΔPOD7–preOP) were calculated as facial swelling and compared between the control and experimental sides.¹,²³

Preoperatively, all patients underwent three-dimensional (3D) facial scanning using CS Face Scan Kit (CS 9600). The CS Face Scan function was launched via CS Imaging 8 software to capture and render a 3D facial image of a subject in less than 15s.²⁴,²⁵

The study involved three time points (Fig. 4):

Fig. 4. Three time points of facial scanning: preoperatively (P0), 3 days postoperatively (P3), and 7 days postoperatively (P7). (A) Preop scan (P0). (B) Postop scan (P3). (C) Postop scan (P7).

• - PO: face scan before surgery, point 0 (Fig. 4A)

  - P3: 3 days after surgery, point 3 (Fig. 4B)

  - P7: 7 days after surgery, point 7 (Fig. 4C)

At POD3 and POD7, the second and third 3D facial scans (P3, P7) were performed to assess postoperative swelling.²⁴

Scans were exported as STL files and imported into the dental application software Materialise MIMICS 21.0 (Materialise HQ Technologielaan, Leuven, Belgium). Materialise MIMICS allows users to evaluate physical models generated from digital facial scans. Preoperative and postoperative scans were superimposed to quantify volumetric differences between the two groups.²⁴ The STL files were imported into the software Materialise 3-matic version 18.0 for superimposition of the pair of scans (P0-P3 and P0-P7) using the “part comparison” specific tool. The analysis function was used to quantify postoperative swelling by visualizing the volumetric differences between scan pairs via histogram color mapping (Fig. 5).²⁵,²⁶,²⁷,²⁸

Fig. 5. Qualitative analysis of the facial swelling scans at different time-point (P0-P3). Red color represents an increase in facial swelling while blue indicates reduction. In the comparison between P0-P3, greater degree of swelling is observed on the right side (placebo) while a relatively small amount of edema is shown on left side (polydeoxyribonucleotide) as shown in the color map.

Periodontal probing depth

Since almost all granulation tissue is replaced by woven bone between 6 and 8 weeks post-extraction,²⁰,²¹ periodontal probing depth (PPD) measurements were performed at long-term follow-up to evaluate periodontal tissue healing and epithelial regeneration.²¹ Right after surgery and at 2 months after surgery, probing depths on the buccal, distal, lingual, and mesial surfaces of the adjacent second molar were evaluated. To minimize bias and maintain blinding, all measurements were recorded to the nearest millimeter by an evaluator who had not operated on the patients. A periodontal probe (PDT Sensor Probes. Zila, Fort Collins, CO, USA) was used for evaluation. PPD reduction, defined as the change (mm) in PPD, was evaluated from baseline (day of surgery) to the 2-month follow-up.²⁸,²⁹

PCOQ

To evaluate postoperative QOL, patients filled out the PCOQ at POD14. Patients answered a set of 11 questions for each side (right and left), based on the Oral Health Impact Profile by Slade and Spencer (Supplementary Table 1, only online).⁴,³⁰

Statistical analysis

The normality of the data was assessed using the Shapiro–Wilk test, and all variables were found to follow a normal distribution (p>0.05). Accordingly, the paired Student’s t-test was employed to compare outcomes between the PDRN and placebo groups in accordance with the split-mouth study design. Statistical significance was evaluated for differences in pain duration, postoperative pain, swelling, PPD, and PCOQ scores (p<0.05). Continuous variables are presented as means±standard deviations. As postoperative pain (VAS) and facial swelling (%) were measured at two time points (POD3 and POD7), Bonferroni correction was applied to adjust for multiple comparisons, thereby reducing the risk of type I error due to repeated measurements and ensuring more stringent control over false-positive findings. All data acquisition and analyses were performed using Microsoft Excel (Microsoft, Redmond, WA, USA) and IBM SPSS Statistics for Windows (ver. 22.0; IBM Corp., Armonk, NY, USA).

RESULTS

The comparative analysis of clinical outcomes between the experimental (PDRN) and control (placebo) groups is presented in Table 2. Each clinical parameter was assessed to evaluate the therapeutic efficacy of PDRN, incorporating both objective clinical indicators and patient-reported outcome measures. A detailed explanation of the findings for each variable is provided in the sections below.

Table 2. Comparison of Postoperative Evaluation Parameters between the Experimental and Control Groups.

		Experimental group (PDRN)	Control group (placebo)	p
Pain duration time (day)
	POD14	3.16±2.26	4.16±3.16	0.082
VAS score
	POD3	3.13±1.92	4.25±1.94	0.027
	POD7	0.43±0.85	1.36±1.81	0.012
Facial swelling (%)
	POD3	3.24±2.22	5.39±2.56	0.002
	POD7	0.27±0.71	1.29±1.97	0.012
Probing depth (mm)
	POD60	3.12±1.16	3.25±1.22	0.164
PCOQ
	POD14	18.70±6.89	24.30±6.18	0.010

PDRN, polydeoxyribonucleotide; POD, postoperative day.

Value are presented as mean±standard deviation.

Pain

The mean pain duration in the experimental and control groups was 3.16±2.26 days and 4.16±3.16 days, respectively. There was no statistical difference in the baseline value of pain duration between the experimental and control groups (p=0.082).

The mean postoperative pain scores in the experimental and control groups were 3.13±1.92 vs. 4.25±1.94 at POD3, and 0.43±0.85 vs. 1.36±1.81 at POD7, respectively. After Bonferroni correction for two time-point comparisons (POD3 and POD7), the experimental group showed greater pain score reductions than the control group (adjusted p=0.027, p=0.012).

Postoperative swelling

The mean percentage of facial swelling in the experimental and control groups was 3.24±2.22 vs. 5.39±2.56 at POD3, and 0.27±0.71 vs. 1.29±1.97 at POD7, respectively. Following Bonferroni correction for two time-point comparisons (POD3 and POD7), a statistically meaningful reduction in postoperative swelling was observed in the experimental group (adjusted p=0.002, p=0.012). As shown in the clinical image (Fig. 6), a marked difference between the experimental and control sides can be observed.³

Fig. 6. Every patients were randomly injected after extraction of both IMTMs on the same day by a single surgeon. The image shows a patient with evident postoperative swelling day 3 on the control side (Normal Saline injection) (A) while swelling is not present on the experimental side (polydeoxyribonucleotide injection) (B).

PPD

At 2 months after surgery, the mean probing depth was 3.12±1.16 mm in the experimental group and 3.25±1.22 mm in the control group. There was no statistical difference between the experimental and control groups regarding the PPD (p=0.164).

PCOQ

The mean total PCOQ score was 18.7±6.89 in the experimental group and 24.3±6.18 in the control group. Patients showed an improvement in QOL in the experimental group compared to the control group, as measured by PCOQ (p=0.010).

DISCUSSION

Third molar surgery is frequently associated with various postoperative complications.³¹ To minimize these complications and alleviate postoperative pain and swelling, numerous studies have evaluated various interventions such as systemic or localized corticosteroids, natural substances, platelet concentrates, and adjunctive laser therapy following IMTM removal.⁴,³²,³³ In the field of oral surgery, PDRN has only been investigated in animal models to evaluate its efficacy on bone formation after tooth extraction.¹⁰ Given the preclinical nature of these studies, the primary focus was limited to histomorphometric analysis of bone formation rather than clinical parameters such as postoperative complications or soft tissue healing. Therefore, this study is the first to evaluate the efficacy of PDRN on postoperative complications in humans after oral surgery.

The experimental side exhibited a statistically meaningful reduction in pain compared to the control side at POD3 and POD7. However, no statistical difference was observed between the two sides in terms of pain duration. This suggests that while patients were able to differentiate the intensity of pain between the right and left sides, it might have been challenging to determine whether the duration of pain was specifically due to the experimental or control side. This may be due to a limitation inherent in the split-mouth study design.³⁴ In addition, factors such as blood clot formation, the influx of food debris into the extraction socket, and the presence of infection could have influenced both the intensity and duration of pain, regardless of group allocation.³⁵ Furthermore, since pain is inherently subjective, both intensity and duration may vary between patients, and objective quantification of pain remains limited. These factors should be considered when interpreting the results.

Postoperative swelling was assessed using the Laskin method, which calculates the sum of two linear measurements between defined reference points.²³,³⁶,³⁷ The linear measurement technique is a simple, non-invasive, reproducible, and inexpensive method to measure the volume of facial swelling.³⁸ However, since the linear measurement method is dependent on the examiner, it can be subjective and prone to measurement errors. To address this limitation, digital software was used in the current study to quantify and evaluate volumetric differences between groups, providing reliable data for objective comparison. The results showed a reduction in postoperative swelling on the experimental side. Through the use of CS Face Scan Kit (CS 9600) and digital software, volumetric difference between experimental and control groups (PI after surgery vs. normal saline injection after surgery) was obtained objectively. This approach not only enhanced the precision and depth of the findings but also provided unprecedented insights into 3D facial changes following IMTM extraction.³⁹ However, despite its accuracy compared to conventional linear measurements, the digital measurement method’s implementation is limited by equipment complexity and high software costs.⁴⁰

Measurement of periodontal pocket depth following IMTM extraction is considered a useful indicator for indirectly assessing the periodontal status of surgical site, healing of soft tissues, and alveolar bone. This parameter is particularly valuable when pre-existing periodontal disease or infection is present. In this study, PPD was evaluated at 2 months postoperatively in both the experimental and control groups, and no statistically significant differences were observed between the two groups. These findings suggest that both groups demonstrated comparable levels of soft tissue healing and alveolar bone preservation. Although PDRN have facilitated the early stages of wound healing, its influence on long-term periodontal pocket depth appears to be limited. It is important to note that post-extraction pocket depth can be modulated by a complex interplay of biological and mechanical factors. Future investigations incorporating extended follow-up durations and radiographic evaluation of alveolar bone regeneration are warranted to more precisely delineate the utility of PDRN in intraoral surgical applications.

In the PCOQ, participants reported a notable improvement on the experimental side in QOL at POD14 after IMTM surgery. In the split-mouth design, patients distinguished the difference between the experimental and control groups in terms of postoperative pain and swelling.³⁷ However, regarding other PCOQ questionnaires, such as speaking or sleeping, they expressed difficulty in determining whether the discomforts were due to the experimental group or the control group. Moreover, cross-contamination or spilling from one group (experimental or control) could have influenced the other group.⁴¹ Therefore, considering the limitations of the split-mouth randomized controlled trial design, a cautious interpretation of the study outcomes is required.

Despite the meaningful clinical outcomes demonstrated in this study, there are several limitations that warrant consideration. First, the absence of histological evaluation limits the findings’ ability to fully elucidate the biological mechanisms underlying the effects of PDRN following IMTM extraction. Second, since the follow-up period was restricted to 2 months, the long-term effects of PDRN on tissue regeneration remain unclear and warrant further investigations through extended follow-up studies. Third, further large-scale studies are required to confirm the findings and validate the results reported in the present study. Additionally, individual variability in healing responses may have influenced the observed outcomes, potentially limiting the generalizability of the results. Moreover, as this study represents a relatively novel application, the dosage reference was limited to previous studies and internal data from Zerone Cellvane, leaving no studies available on changes in biological efficacy with dosage variation.⁴²,⁴³ Finally, although the study employed a placebo-controlled design, it did not incorporate direct comparison analyses with other regenerative modalities such as platelet-rich plasma, enamel matrix derivative, or hyaluronic acid. Consequently, future head-to-head comparison studies are required to determine PDRN’s relative clinical efficacy and therapeutic potential compared with these established interventions.

In conclusion, the present study has shown that PI following IMTM extraction reduced postoperative pain, swelling, and patients’ discomfort compared to the placebo group. These findings support that the clinical use of PDRN is an effective adjunctive therapy for mitigating postoperative complications in oral surgery. Furthermore, this study offers novel clinical insight supporting the potential application of PDRN in oral surgery and emphasizes the necessity for continued research to define its efficacy in postoperative applications.

SUPPLEMENTARY MATERIAL

Supplementary Table 1

Patient-Centered Outcome Questionnaire, OHIP-Based Version