Bone Height and Extractions Study

Study Overview
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Brief Summary
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A coronectomy is often chosen over complete extraction of a lower third molar when the tooth appears to be in close proximity to the inferior dental (ID) canal, as assessed on a plain radiograph or a cone beam computer tomograph (CBCT). Following a coronectomy, the roots of the third molar may migrate in a coronal direction. This effect, along with the bone-preserving technique of a coronectomy over extraction, may provide increased bone height distal to the lower second molars, when compared to extraction. Partially erupted lower third molars, specifically those with mesio-angular impactions, are commonly associated with reduced bone height distal to lower second molars, and cause damage to the periodontal support of these neighboring teeth. It is assumed that maintenance of the impacted third molars or extraction of these teeth may compromise the periodontal status of the lower second molars. This study will investigate if coronectomy improves the bone levels, and therefore the periodontal status, of lower second molars, and may propose an indication for a coronectomy regardless of the proximity of the tooth to the ID canal. Coronectomies were first proposed as a treatment option just over thirty years ago, but there are very few long-term studies on the procedure reported in the literature. To the best of the investigator's knowledge, this will be the first randomised controlled trial comparing the bone height distal to the lower second molar following a coronectomy or extraction of the lower third molar.

Official Title
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A Randomised Controlled Trial to Assess the Alveolar Bone Height Distal to Lower Second Molar Following Either Coronectomy or Extraction of the Adjacent Impacted Lower Third Molar

Conditions
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Alveolar Bone Loss, Periodontal Attachment Loss, Periodontal Pocket

Intervention / Treatment
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* Procedure: Third molar surgery


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients requiring extraction of both lower third molars Both lower third molars to have mesio-angular impa ctions, as assessed by location of the contact point between the crown of the third molar and the cemento-enamel junction (CEJ) of the second molar and the angulation of the third molar Both lower third molars must lie above or clear of the ID canal as assessed on a plain radiograph or CBCT Presence of lower second molars Patients must be ≥18yrs old Patients willing to attend follow up appointments Exclusion Criteria: Lower third molars with caries, periapical pathology or associated lesions such as cysts Patients who are immunocompromised, have a history of or due to have head and neck radiotherapy, chemotherapy, have previously been given or due to start intravenous bisphosphonates Smokers (>5 cigarettes/day) Patients involved in current research or have recently been involved with research prior to recruitment

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Interventional Model Description: Split-mouth
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Third molar surgery<br>Split mouth comparison of effect of complete third molar removal vs coronectomy of contralateral third molar | Procedure: Third molar surgery<br>* Comparing complete removal of third molar with removal of crown only on contralateral side<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Linear bone height distal to lower second molar tooth | Assessed by comparison of periapical radiographs pre- and post-intervention | Six months surgical intervention |