A deeply impacted wisdom tooth does not always need a larger surgical window. Sometimes, the more conservative solution is to make the tooth smaller instead of removing more surrounding bone.
This is where strategic tooth sectioning becomes important during odontectomy.
Impacted mandibular third molars can present in vertical, mesioangular, distoangular or horizontal positions, with surgical difficulty influenced by depth, available space, root morphology and the relationship between the tooth and surrounding anatomical structures.
Rather than treating every impacted tooth as one solid object that must be removed intact, the surgeon may divide the crown or roots into smaller segments. This changes the geometry of the tooth and can create a more favorable path of removal.
Odontectomy Is More Than Simply Extracting a Wisdom Tooth
In oral-surgery literature, odontectomy is commonly used to describe surgical removal of an impacted tooth. Depending on the case, the procedure may involve flap elevation, controlled bone removal and odontosection, or tooth sectioning, before the individual segments are delivered.
Importantly, not every impacted third molar requires immediate surgical removal.
The 2024 clinical practice guideline from the Spanish Society of Oral Surgery (SECIB) recommends basing treatment decisions on clinical and radiographic assessment rather than automatically extracting every asymptomatic third molar.
Surgery may be considered when there is clinically relevant pathology or risk, such as recurrent pericoronitis, caries, periodontal problems, damage to the adjacent second molar, cystic change or other complications.
Once surgery is indicated, however, the next question becomes important:
How much bone really needs to be removed before the tooth can be delivered?
Why Tooth Sectioning Can Change the Surgical Strategy
Consider a horizontally impacted lower third molar with its crown positioned against the second molar.
Removing the entire tooth in one piece can require significant surrounding bone removal simply to create enough space for elevation.
Sectioning changes the mechanical problem.
By dividing the crown, separating the roots or creating several smaller tooth segments, the clinician may reduce the amount of resistance that must be overcome during delivery.
A particularly interesting 2026 study by Wu and colleagues examined 400 patients with horizontally impacted mandibular third molars. Their digitally planned cross-sectioning protocol divided the tooth into four segments and was designed specifically to reduce resistance from surrounding bone and the adjacent tooth.
Compared with the traditional technique used in the study, the cross-sectioning group showed shorter operating times and reductions in postoperative pain and swelling.
The study used a specific digitally calculated cutting protocol, so its exact measurements should not be applied universally. The more valuable principle is broader:
Strategic tooth segmentation can sometimes reduce the need to solve every surgical resistance problem by removing additional bone.
Crown Sectioning and Root Separation Are Not the Same Task
Bur selection during odontectomy should follow the surgical objective.
Broad bone exposure and deep root separation require very different cutting geometries.
A round surgical bur may be useful for localized bone removal. A Lindemann bur can provide efficient directional bone cutting during osteotomy. A fissure carbide bur creates a more linear cut and may be useful for crown or root sectioning.
For example, the MR.Bur HP166 Lindemann Bur HP is intended for bone cutting, surgical extraction and separation procedures, making it relevant during the access and osteotomy stage.
The MR.Bur Tungsten Carbide Fissure MOS Bur HP is another option where a defined linear section through tooth or bone is required. MR.Bur lists wisdom-tooth sectioning, tooth separation and bone cutting among its applications.
But deeper tooth separation introduces another challenge: reach.
Where Does MR.Bur 77L Fit?
The MR.Bur 77L Tooth Sectioning Diamond Bur is designed specifically for wisdom-tooth sectioning and tooth separation.
It features a 1.2 mm working head, coarse green-band diamond design and 32 mm overall length, giving the bur extended access when the required separation extends deeper into an impacted tooth or root complex.
MR.Bur positions 77L as an FG tooth-sectioning bur for situations where deeper access is required during impacted wisdom-tooth separation.
This makes the bur particularly relevant after sufficient surgical exposure has already been created and the objective changes from removing bone to modifying the tooth itself.
Possible sectioning objectives include:
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separating the crown from the root complex;
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dividing mesial and distal roots;
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extending a section through a deeply positioned tooth;
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reducing a large tooth into smaller segments that can be removed more conservatively.
Its longer design, however, should never be interpreted as an invitation to simply cut deeper.
Greater reach increases access. It also makes depth awareness more important.
Why the Lingual Side Deserves Special Attention
One reason controlled sectioning matters is the anatomy immediately beyond the tooth.
A 2023 systematic review and meta-analysis by Lin and colleagues examined the position of the lingual nerve in the posterior mandible.
At the third-molar region, approximately 35.2% of lingual nerves were reported in contact with the lingual plate, while approximately 6.3% coursed above the alveolar crest.
This anatomical variability helps explain why sectioning direction and depth should be planned rather than treated as a simple instruction to “cut completely through the tooth.”
A deep separation groove does not necessarily mean the bur must be advanced uncontrollably through the lingual aspect.
Visibility, anatomy and controlled completion of the separation remain more important than maximum bur penetration.
What About the Inferior Alveolar Nerve?
The relationship between mandibular third-molar roots and the inferior alveolar canal is another major component of preoperative planning.
Panoramic radiography is commonly used for initial assessment. CBCT can provide three-dimensional information when the root-canal relationship is uncertain or when additional information may affect treatment planning.
However, more imaging does not automatically mean fewer nerve injuries.
A systematic review by Robbins and colleagues included seven randomized controlled trials comparing CBCT with conventional panoramic assessment in higher-risk mandibular third-molar cases. The authors found moderate-quality evidence that routine CBCT did not translate into a reduced incidence of inferior dental nerve injury.
Therefore, CBCT is better considered a selective planning tool, not a routine requirement before every odontectomy.
A More Logical Bur Workflow
Rather than expecting one bur to perform the entire surgical procedure, instrumentation can be selected according to each objective:
Assess → Access → Expose → Section → Separate → Deliver
During access, a surgical round or Lindemann carbide bur may assist with controlled osteotomy.
When a more defined linear cut is needed, a fissure carbide geometry may be selected.
When the challenge becomes deep tooth or root separation, the extended geometry of 77L can become particularly useful.
This workflow also illustrates an important difference between osteotomy and odontosection:
Osteotomy changes the surrounding bone. Odontosection changes the tooth.
The most conservative solution may involve balancing both.
Frequently Asked Questions
What is odontectomy?
Odontectomy commonly refers to the surgical removal of an impacted tooth. It may include flap elevation, bone removal and sectioning of the tooth before removal.
Why are wisdom teeth sectioned during odontectomy?
Sectioning reduces the dimensions of the tooth and allows individual crown or root segments to follow more favorable removal paths. In selected cases, this can reduce the amount of additional bone removal required.
Which bur is suitable for wisdom-tooth sectioning?
The correct bur depends on the surgical objective. Fissure carbide burs can provide linear sectioning, while longer sectioning burs can improve access to deeper tooth structures. MR.Bur 77L is specifically designed for wisdom-tooth and tooth separation applications.
Is CBCT required before every impacted wisdom-tooth surgery?
No. Current evidence does not support routine CBCT for every third-molar extraction. It is most useful when three-dimensional information could meaningfully influence treatment planning.
The Clinical Takeaway
Successful odontectomy is not simply about removing an impacted tooth as quickly as possible.
It is about understanding where the resistance comes from.
If bone is obstructing access, controlled osteotomy may be necessary. If the size or orientation of the tooth is preventing delivery, strategic tooth sectioning may be the more conservative solution.
And when that section needs to extend deeper into the tooth or root complex, bur geometry matters.
The 32 mm MR.Bur 77L provides an extended, narrow coarse-diamond design specifically intended for tooth and wisdom-tooth separation.
The principle is simple:
Remove the bone that needs to be removed. Section the tooth where it creates a better path. And make every cut with anatomy, access and surgical control in mind.
