Precise Minimally Invasive Extraction of Impacted Teeth: Standardized Techniques and Management Practices

Impacted mandibular third molars, commonly referred to as impacted wisdom teeth, are teeth that fail to erupt into the dental arch within the expected developmental window, often due to lack of space, obstruction by adjacent teeth, or unfavourable angulation. These impactions are highly prevalent worldwide, with estimates suggesting that up to 72% of individuals experience some form of mandibular third molar impaction during their lifetime^1,2,3. The Pell and Gregory classification system is a widely adopted framework for evaluating the difficulty of impacted mandibular third molar extractions. It categorizes impactions based on the relationship of the tooth to the anterior border of the mandibular ramus^4,5. In Class I, the third molar is positioned entirely anterior to the ramus, with adequate space to accommodate the crown, making surgical access relatively straightforward^6,7. Class II impactions occur when the distal portion of the crown is partially covered by the ramus, indicating limited space and necessitating moderate bone removal^8,9. While in Class III, the third molar is completely embedded within the ramus, lacking sufficient space for eruption^10,11. These cases are often deeply impacted and present the greatest surgical challenge due to their proximity to the inferior alveolar nerve and the need for extensive bone contouring and segmental tooth sectioning⁹.

Traditional extraction techniques for impacted mandibular third molars often involve extensive soft tissue reflection, ostectomy, and tooth elevation using rotary instruments or chisels¹². One common approach is the envelope flap technique, which involves a long crestal incision extending along the gingival margin of adjacent teeth to allow wide surgical access^13,14. Another widely used method is the triangular flap technique, incorporating a vertical releasing incision to improve visibility and mobility of the flap^15,16. These techniques typically require substantial bone removal to expose the impacted crown, particularly in Class II and III impactions, followed by elevation or tooth sectioning using rotary burs or elevators. While effective, these traditional methods are often associated with increased operative times, greater postoperative pain, higher risk of nerve injury, alveolar osteitis, and delayed healing due to the extensive manipulation of hard and soft tissues^17,18.

In response to these challenges, minimally invasive techniques have been developed to reduce surgical trauma and improve patient outcomes¹⁹. Orthodontic-assisted extrusion allows safer repositioning of teeth near the inferior alveolar nerve before extraction, significantly lowering nerve injury risks^20,21. In addition, the inward fragmentation technique (IFT), which employs 3D-planned sectioning to remove the tooth internally with minimal bone removal²², and piezoelectric surgery, which enables precise, low-trauma bone cutting and reduces the risk of nerve injury compared to rotary instruments²³. Advances such as robot-assisted surgery²⁴ and 3D-printed surgical guides²⁵ further enhance precision and reduce tissue damage. Xu and Zhang conducted a study comparing these approaches for the extraction of impacted mandibular third molars, finding that the minimally invasive method resulted in shorter operation times and fewer intraoperative and postoperative complications²⁶. These advancements underscore the importance of adopting minimally invasive techniques in the extraction of impacted teeth. By minimizing surgical trauma and preserving surrounding anatomical structures, these methods not only enhance patient comfort but also contribute to improved healing and reduced complication rates.

This study aims to present a standardized, step-by-step approach for the precise, minimally invasive extraction of impacted teeth, focusing on controlled incisions, careful bone contouring, and segmental tooth removal. Our goal is to enhance surgical accuracy, minimize complications, and improve postoperative recovery through structured protocol implementation.

This study was approved by the Ethics Committee of The Second Affiliated Hospital of Zhejiang University (Approval No. 2025-1114). All participants provided written informed consent before their inclusion in the study, following the Declaration of Helsinki.

1. Patient preparation

NOTE: This study enrolled systemically healthy adults aged between 18-40 years with radiographically confirmed mandibular third molar impactions classified as Pell and Gregory Class I, II, or III. Inclusion required the absence of associated pathology and the availability of preoperative imaging. Exclusion criteria comprised any systemic condition compromising wound healing, active local infection, history of mandibular surgery, pregnancy, and current use of medications affecting bone turnover or soft tissue repair.

1. Perform preoperative examinations, including assessing the position of the impacted tooth, the status of the apex, and obtaining a panoramic X-ray.
2. Educate the patient about the procedure, potential complications, and postoperative care.
3. Administer local anesthesia with 2% lidocaine or 4% articaine, covering the gingiva, periosteum, and surrounding soft tissues of the impacted tooth. Confirm adequate anesthetization by probing the mucosa and periosteum with a blunt instrument; proceed only if no pain response is elicited.

2. Surgical steps

1. General surgical precautions
   NOTE: Use sharp instruments and high-speed burs with irrigation and caution near vital structures. Follow sterilization protocols for all instruments and materials.
   1. Verify the inferior alveolar nerve position using cone-beam computed tomography (CBCT), where the canal appears as a dark tubular space with bright borders, allowing evaluation of its proximity to the tooth roots.
   2. Design the incision, then use a periosteal elevator to carefully raise the mucoperiosteal flap, gently reflecting and retracting the tissue to minimize trauma.
   3. Once proper anesthetization is confirmed, make a 1 cm vertical incision in the mesial direction of the impacted tooth with a No. 15 surgical blade, extending to the periosteal layer (Figure 1).
   4. Make the incision long enough to fully expose the surgical site, which includes the area covering the crown of the impacted third molar and the nearby alveolar bone, while keeping soft tissue damage to a minimum.
   5. Use a periosteal elevator to carefully separate the gingiva and mucoperiosteal flap, gradually exposing the mesial, distal, buccal, and lingual bone structures around the impacted tooth.
2. Tooth sectioning
   1. Use a high-speed turbine handpiece (200,000-400,000 rpm, torque 0.02-0.05 N·cm) with a long fissure bur to section the impacted tooth at the mesial-distal junction. Cut to the root bifurcation, ensuring the cut direction aligns with the root axis to avoid damaging the surrounding bone (Figure 2).
   2. Confirm complete sectioning by clearing the area with suction and adequate lighting to visualize a distinct dark line between the segments. Then, use a dental probe to gently move each part and check for independent mobility, confirming full separation.
3. Bone contouring and the distal root removal
   1. If necessary, remove a small amount of bone covering the tooth root using a round or long fissure bur mounted on a high-speed handpiece (200,000-400,000 rpm) with copious sterile saline irrigation, to reduce resistance during extraction.
   2. Insert a straight elevator into the gap between the tooth segments and gently rotate to loosen the distal root.
   3. Once loosened, extract the distal root using a straight elevator (Figure 3).
4. The mesial root removal, cleaning, and inspecting the socket
   NOTE: Visually identify the mesial root by its separation line, color contrast, or mobility under light and suction.
   1. Place a triangular elevator into the distal socket, using a lever action to carefully extract the mesial root (Figure 4).
   2. If needed, use a bone chisel or other dental instruments, such as a periotome, luxator, or small straight elevator, to further separate the root.
   3. Remove inflammatory granulation tissue and any remaining root fragments from the socket using a curette or suction tip.
      NOTE: The inflamed tissue appears reddish, friable, and distinct from the pale surrounding bone and is visualized under direct illumination and suction.
   4. Rinse the socket with 10-20 mL of saline to ensure no foreign matter remains.
      NOTE: Maintain saline at room temperature (20-25 °C) before use.
   5. Inspect the socket for integrity, checking for bone damage and confirming that the alveolar septum is intact (Figure 4).
5. Gingiva repositioning and wound suturing
   1. Reposition the gingiva and mucoperiosteal flap to cover the incision, ensuring soft tissue edges align properly.
   2. Use 4-0 or 5-0 absorbable sutures to close the incision, placing 1-2 stitches to control bleeding and minimize wound exposure (Figure 5).
      NOTE: Store sutures between 15-30 °C in a dry, sterile environment.

3. Postoperative care and management

1. Control postoperative bleeding and postoperative education
   1. Place a sterile cotton pad at the incision site and instruct the patient to gently bite down for 30 min to control bleeding.
   2. Advise the patient to avoid rinsing, sucking, or consuming spicy foods within the first 24 h post-surgery.
   3. Encourage the patient to start using warm salt water or a mouthwash to clean the mouth 48 h after surgery.
   4. Instruct the patient to avoid vigorous physical activities and keep their head elevated to reduce the risk of bleeding.
2. Medications
   1. Routinely prescribe antibiotics (such as 500 mg of amoxicillin, 3 times daily for 3-5 days) to prevent infection post-surgery.
   2. If necessary, provide nonsteroidal anti-inflammatory drugs (such as 400 mg of ibuprofen every 6-8 h as needed for pain, not exceeding 2400 mg/day) to manage postoperative pain.
3. Follow-up plan
   1. Schedule a follow-up appointment one week after surgery to check the healing progress and assess for any complications (such as dry socket, infection, etc.).
4. Waste management
   1. Dispose of blood-soaked gauze, tissues, and gloves in designated biohazard containers.
   2. Discard used anesthetic syringes and needles in approved sharps disposal containers.
      NOTE: Follow institutional and regulatory guidelines for all clinical waste handling and disposal.

A standardized minimally invasive protocol was applied in a clinical cohort of 30 patients undergoing extraction of impacted mandibular third molars. Patients ranged in age from 19 to 34 years (mean age 26.2 ± 4.3 years), as age may affect surgical difficulty and healing. The cohort included 17 males and 13 females. According to the Pell and Gregory classification, 10 cases were Class I, 12 were Class II, and 8 were Class III impactions, as determined from the radiological images and intraoperative evaluation27,28.

All surgical procedures were completed without intraoperative complications. Operative time for each patient was recorded from incision to completion of wound closure using a digital timer. Group means were calculated from individual patient data within each Pell and Gregory class. The mean operative time was 19.4 ± 3.2 min, with significantly longer durations in Class III cases (22.7 ± 2.9 min) compared to Class I (16.8 ± 2.1 min) and Class II (18.9 ± 2.6 min) (p = 0.0006, Analysis of Variance [ANOVA]) (Table 1). These findings underscore the protocol's efficiency even in complex anatomical scenarios, facilitated by the stepwise approach involving controlled incision (Figure 1), segmental sectioning (Figure 2), and conservative bone removal (Figure 3).

Postoperative pain was assessed using a 10-point Visual Analog Scale (VAS), where 0 indicated "no pain" and 10 indicated "worst imaginable pain." Each patient self-reported their pain score at 24 h and again at 48 h after surgery. The individual scores were used to calculate group means ± SD at each time point. Statistical comparison of the two time points was performed using a paired t-test. Scores significantly decreased from 3.1 ± 1.1 at 24 h to 1.7 ± 0.9 at 48 h (paired t-test, p < 0.0001), reflecting low postoperative discomfort (Table 2).

Although no a priori power calculation was conducted, a post-hoc analysis was performed to assess whether the sample size was adequate to detect the observed reduction in VAS pain scores. The effect size was calculated using Cohen's d:

Using the 24 h and 48 h means (3.1 ± 1.1 and 1.7 ± 0.9; n = 30), this yielded d = 1.39 and a post-hoc power of 1.0 (α = 0.05). This indicates that the study sample was more than sufficient to detect clinically meaningful changes in postoperative pain.

This rapid pain reduction supports the efficacy of minimally traumatic soft tissue handling and tension-free wound closure using absorbable sutures (Figure 5). No cases of dry socket, infection, or nerve injury were recorded. One instance of minor wound dehiscence (3.3%) was observed and resolved without intervention. Chi-square analysis revealed no significant correlation between impaction class and complication incidence (p = 0.62), suggesting consistent procedural safety across varying impaction depths (Table 3).

Figure 1: Vertical incision design for flap elevation. Please click here to view a larger version of this figure.

Figure 2: Tooth sectioning technique. Sectioning at the mesial-distal junction (black star) using a high-speed bur and extension of the cut toward the root bifurcation to separate the crown and roots. Please click here to view a larger version of this figure.

Figure 3: Distal root extraction. Elevation and extraction of the distal root after bone contouring. Please click here to view a larger version of this figure.

Figure 4: Mesial root removal and socket check using triangular elevator. The alveolar septum is indicated with a black star. Please click here to view a larger version of this figure.

Figure 5: Wound closure with absorbable sutures. Please click here to view a larger version of this figure.

Table 1: Operative times by impaction class. Individual operative times for each patient grouped by Pell and Gregory impaction class, with class means expressed as mean ± SD. Overall comparison of class means was performed using a one-way ANOVA.

Table 2: Postoperative VAS pain scores. Frequency distribution of postoperative pain scores on the 10-point VAS at 24 and 48 h, with mean VAS scores expressed as mean ± SD. Comparison between time points was performed using a paired t-test.

Table 3: Postoperative complication rates. Complication frequencies by Pell and Gregory impaction class. Comparison among classes was performed using a chi-square test.

The presented protocol for minimally invasive extraction of impacted mandibular third molars marks a significant advancement in oral surgical practice, prioritizing surgical precision, procedural safety, and the preservation of critical anatomical structures. A key determinant of its success is the carefully designed incision combined with precise and controlled flap elevation. The mesially positioned vertical incision, limited to approximately 1 cm, reduces soft tissue trauma and allows targeted access to the impacted tooth. The elevation of the mucoperiosteal flap is performed in a stepwise and atraumatic fashion, exposing critical bony landmarks while preserving vascular integrity. These foundational steps are critical for creating a clear and controlled surgical field that minimizes operative time and facilitates clean closure, reducing the postoperative complications such as wound dehiscence or delayed epithelialization. Equally crucial is the sectioning of the tooth and precise bone contouring, which allows for the stepwise removal of tooth segments with minimal disruption to surrounding structures. By separating the tooth at the mesial-distal junction using a high-speed fissure bur aligned with the root axis, the surgeon minimizes stress transmission to the surrounding alveolar bone. This approach enhances intraoperative visibility and control and also significantly reduces the risk of root fracture and inadvertent damage to the inferior alveolar nerve, a complication historically associated with high morbidity. Contemporary evidence supports the notion that staged, segmental tooth extraction techniques, particularly when guided by preoperative imaging, lead to improved clinical outcomes with significantly lower nerve morbidity and inflammatory sequelae. If these steps are omitted or improperly executed, specific adverse outcomes may result. For instance, an inadequately planned or poorly placed incision can lead to insufficient surgical access, increased soft tissue trauma, and delayed healing. Failure to perform atraumatic flap elevation may compromise vascular integrity, predisposing the site to wound dehiscence^29,30. Without conservative bone contouring, resistance during root elevation may heighten operative time and trauma. Therefore, each step, from controlled incision design to staged root removal, is technical and protective in nature, serving to preserve anatomical structures and optimize healing trajectories.

Despite the strengths of this approach, adjustments and intraoperative refinements are occasionally necessary to address anatomical variability or unforeseen surgical challenges. In cases of dilacerated or ankylosed roots, additional bone contouring or the use of piezoelectric or magneto-dynamic instruments can facilitate segmental mobilization while reducing trauma to adjacent tissues. These methods have shown favorable results in pilot studies comparing conventional tools with ultrasonic surgical alternatives, particularly in terms of patient comfort and wound stability³¹. Furthermore, digital imaging and intraoperative navigation can be leveraged to pre-plan osteotomies and root sectioning, providing surgeons with a higher degree of predictability and control, especially in high-risk impactions.

When compared to traditional open-flap, block excision, or ostectomy-based approaches, this minimally invasive method clearly demonstrates clinical superiority across several metrics. These include reduced intraoperative bleeding, shorter operative times, lower postoperative pain scores, and decreased incidence of neurologic sequelae. A recent comparative analysis noted that minimally invasive procedures are associated with a statistically significant reduction in soft tissue disruption and improved patient-reported outcomes, including faster return to normal function and higher satisfaction rates³². This is particularly relevant given the high incidence of third molar extractions globally and the associated burden of complications that accompany conventional methods. A recent study by Gojayeva et al. evaluated postoperative outcomes in 100 patients undergoing mandibular third molar extraction and reported complication rates of 13% for alveolar osteitis and 6% for wound dehiscence, along with measurable impacts on trismus, pain, and oral health-related quality of life. Their analysis identified positive correlations between patient age, surgical duration, and the incidence of complications, highlighting the clinical burden associated with prolonged or invasive procedures³³. In contrast, our study recorded no instances of infection, alveolar osteitis, or nerve injury, and only a single case of minor wound dehiscence (3.3%), which resolved without intervention. Moreover, postoperative pain scores declined significantly within 48 h, and no functional limitations were reported.

The limitations of the method, though relatively few, warrant acknowledgment. The technique requires advanced surgical skill and anatomical precision, particularly near neural structures or in cases with complex root anatomy. In deep impactions or associated pathology, the minimally invasive advantage may be reduced. While the protocol standardizes third molar extraction, its application to other tooth types may require modification. Additionally, the single-center design, limited sample size, lack of a control group, and short follow-up restrict generalizability and long-term assessment. Operator dependency further underscores the need for validation through larger, multicenter studies.

The clinical significance and broader applicability of this technique are equally noteworthy. Beyond its role in routine third molar extractions, the protocol holds substantial value in interdisciplinary treatment planning, such as orthodontic interventions, implant site development, and management of medically compromised patients. By enabling atraumatic extractions with limited bone removal and soft tissue disruption, it maintains alveolar ridge dimensions, which is critical for orthodontic planning and simplifies subsequent implant placement without extensive grafting. Additionally, the reduced surgical time and tissue trauma minimize systemic stress and postoperative complications. With the integration of digital technology, such as touch-controlled surgical devices and custom 3D-printed surgical guides, the precision of this protocol is further enhanced, enabling surgeons to replicate outcomes consistently across a range of clinical scenarios^34,35.