The surgical challenge of "kissing molars"

The phenomenon of "kissing molars" (KM) represents a rare variant of dental impaction, characterized by the contact of the occlusal surfaces of two molars within the same follicular space, with their roots pointing in opposite directions. This atypical anatomical configuration, involving here the mandibular second and third molars, confronts the surgeon with critical operative risks: injury to the inferior alveolar nerve (IAN) and iatrogenic bone weakening that can lead to a per- or postoperative mandibular fracture.

Objective and rationale of the sagittal osteotomy approach

The objective of this case report is to present a technical alternative to conventional exodontia for the management of a 26-year-old patient presenting with severely impacted third molars (units 47 and 48). Faced with an IAN positioned lingually and in intimate contact with the crowns, the study evaluates the use of sagittal split ramus osteotomy (SSRO). The hypothesis tested is that this approach, traditionally reserved for orthognathic surgery, allows for optimized visual access and direct protection of the neurovascular bundle. The challenge is to demonstrate that SSRO reduces morbidity and avoids the extensive osteotomy often required during a classic extraction in this complex anatomical region.

Methodology

This case report documents the surgical management of a 26-year-old male patient presenting with a rare dental impaction known as "kissing molars". The units involved were the right mandibular second and third molars (47 and 48), characterized by crowns facing each other within a single follicular space in the region of the mandibular angle and ramus.

The diagnostic and surgical protocol was structured as follows:

• Preoperative imaging: Use of panoramic radiography and cone beam computed tomography (CBCT). These examinations revealed close contact between the teeth and the inferior alveolar nerve, the latter being located on the lingual side.
• Surgical technique: Sagittal split ramus osteotomy (SSRO) performed according to Dal Pont's principles. The protocol utilized a reciprocating saw for the cortical osteotomy, followed by bone segment separation with a chisel to allow direct visualization of the neurovascular bundle and extraction of teeth 47 and 48.
• Additional procedure: Teeth 18, 28 and 38 were also extracted during the same surgery.
• Stabilization: Repositioning of the mandible and internal fixation using a 2.0 mm system titanium mini-plate, secured by four monocortical screws.
• Postoperative follow-up: Clinical and tomographic evaluation at 3 months to verify occlusion stability, mouth opening, absence of paresthesia, and bone formation in the extraction area.

Clinical results and surgical observations

The surgical procedure involved the complete extraction of teeth 18, 28, 38, 47, and 48 in this 26-year-old patient. The use of sagittal split ramus osteotomy (SSRO) for units 47 and 48 provided direct access and optimal visibility over the entire surgical field.

The intraoperative observations and reported clinical results are as follows:

• Nerve preservation: The technique allowed for direct visualization of the inferior alveolar nerve (IAN), initially located in a lingual position and in close contact with the dental crowns. No iatrogenic injury was reported.
• Complications: The study reports no major intraoperative or postoperative complications. The risk of mandibular fracture, associated with conventional alveolotomy for deep impactions, was controlled by the segmental approach.
• Morbidity and function: The patient presented low postoperative morbidity. Clinical evaluations report good mouth opening and stable occlusion.
• Follow-up imaging: Facial tomography confirms the adequate repositioning of the bone segments and the presence of bone neoformation in the extraction area.

In concrete terms, OSRM has transformed a complex extraction with a high risk of fracture and nerve damage into a controlled procedure, with functional recovery without sensory sequelae.

Clinical analysis and surgical interest

The outcome of this procedure demonstrates that sagittal ramus osteotomy, although traditionally reserved for orthognathic surgery, offers major advantages for complex extractions. In this specific case of "kissing molars", the technique allowed a high-risk procedure to be transformed into a controlled intervention thanks to superior surgical access. Unlike conventional exodontia, SRO avoids blind odontosections near the inferior alveolar nerve, thereby drastically reducing the risk of neurological trauma.

Limits and comparison with the literature

The weak point of this approach lies in its technicality and the need for a suitable technical platform (general anesthesia, maxillofacial surgery instrumentation). As this is a single case report, these results cannot be generalized to all impactions, but they corroborate data suggesting that OSRM is a viable alternative to coronectomy or conventional extraction when bone preservation is critical.

Implications for practice

In the practice, this study highlights the importance of rigorous preoperative planning via CBCT to identify cases where conventional access would be deleterious. For the practitioner, OSRM appears to be an effective salvage solution for deep ectopic impactions, allowing recovery without nerve sequelae or excessive residual mandibular fragility.

Study summary

Sagittal ramus osteotomy allowed for the safe extraction of "kissing" molars in this patient. This surgical approach ensured direct visualization of the inferior alveolar nerve, preventing any nerve injury and iatrogenic fracture despite the extreme depth of the impaction and the close proximity of the neurovascular bundle.

In concrete terms, for the practitioner:

• Prioritize sagittal osteotomy for severe impactions: it offers direct visual access to the inferior alveolar nerve, securing the procedure where conventional exodontia remains blind and risky when faced with opposing roots.
• Preserve mandibular mechanical strength: by avoiding the massive bone milling required to expose inverted crowns, this technique limits cortical destruction and drastically reduces the risk of per- and post-operative fracture.
• Secure the neurological prognosis: controlled surgical exposure allows for active protection of the neurovascular bundle during critical phases of tooth separation, thus minimizing the risks of paresthesia.

Technical lexicon of the study

Kissing molars: A rare form of dental impaction characterized by the contact of the occlusal surfaces of two molars within the same follicular space, with roots oriented in opposite directions.

Sagittal Split Ramus Osteotomy (SSRO): Surgical technique providing direct access and visualization of the surgical site, used here as an alternative to conventional extraction to reduce the risk of major complications.

Follicular space: Single cavity containing the crowns of the impacted molars, the fusion of which is a diagnostic criterion for the kissing molars phenomenon.

CBCT (Cone Beam Computed Tomography): Three-dimensional imaging used to evaluate the proximity relationship between the dental roots and the inferior alveolar nerve, located here in a lingual position.

Iatrogenic fracture: Accidental rupture of the mandible that may occur during or after surgery due to the significant bone resection sometimes required during complex extractions.

Morbidity: A term referring to the negative effects or potential complications associated with the surgical procedure, which the MORS technique allows to be kept at a low level according to the authors.

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